diff --git a/js/ArgParser.js b/js/ArgParser.js
index deb1be5dd..0d892f7d0 100755
--- a/js/ArgParser.js
+++ b/js/ArgParser.js
@@ -14,7 +14,11 @@ Options and their defaults are:
 	defaultName: null,
 	defaultValue: null,
 	noNames: false,
-	cascadeDefaults: false
+	cascadeDefaults: false,
+	allowEval: true
+	globals: null
+
+`globals` is the global variable object provided to evaluated parameters
 
 \*/
 (function(){
@@ -22,23 +26,26 @@ Options and their defaults are:
 /*jslint node: true */
 "use strict";
 
+var Sandbox = require("./Sandbox.js").Sandbox;
+
 var ArgParser = function(argString,options) {
 	var parseToken = function(match,p) {
-		var n;
-		if(match[p]) // Double quoted
-			n = match[p];
-		else if(match[p+1]) // Single quoted
-			n = match[p+1];
-		else if(match[p+2]) // Double-square-bracket quoted
-			n = match[p+2];
-		else if(match[p+3]) // Double-brace quoted
-			n = match[p+3];
-		else if(match[p+4]) // Unquoted
-			n = match[p+4];
-		else if(match[p+5]) // empty quote
-			n = "";
-		return n;
-	};
+			var n;
+			if(match[p]) { // Double quoted
+				n = match[p];
+			} else if(match[p+1]) { // Single quoted
+				n = match[p+1];
+			} else if(match[p+2]) { // Double-square-bracket quoted
+				n = match[p+2];
+			} else if(match[p+3]) { // Double-brace quoted
+				n = options.allowEval === false ? match[p+3] : Sandbox(match[p+3],options.globals);
+			} else if(match[p+4]) { // Unquoted
+				n = match[p+4];
+			} else if(match[p+5]) { // empty quote
+				n = "";
+			}
+			return n;
+		};
 	this.byPos = [];
 	var dblQuote = "(?:\"((?:(?:\\\\\")|[^\"])+)\")",
 		sngQuote = "(?:'((?:(?:\\\\\')|[^'])+)')",
diff --git a/js/Sandbox.js b/js/Sandbox.js
new file mode 100644
index 000000000..3cc61eccc
--- /dev/null
+++ b/js/Sandbox.js
@@ -0,0 +1,53 @@
+/*\
+title: js/Sandbox.js
+
+Execute a fragment of JavaScript in a sandbox
+
+\*/
+(function(){
+
+/*jslint node: true */
+"use strict";
+
+var uglify = require("uglify-js");
+
+var safeEval = function(e) {
+	return eval(e);
+};
+
+var Sandbox = function(code,globals) {
+	var globalNames = [],
+		globalValues = [],
+		collectGlobals = function(globals) {
+			if(globals) {
+				for(var g in globals) {
+					globalNames.push(g);
+					globalValues.push(globals[g]);
+				}
+			}
+		};
+	// Collect the supplied globals
+	collectGlobals(globals);
+	// Add the default globals
+	collectGlobals({
+		tiddlywiki: "5"
+	});
+	// Compose the code
+	var out = [];
+	out.push("(function(")
+	out.push(globalNames.join(","));
+	out.push(") { return ");
+	out.push(code);
+	out.push(";})");
+	// Parse the code
+	var tree = uglify.parser.parse(out.join(""));
+	// XXX: Sanitise the code by checking for references to globals
+	// Recompile the code
+	var compiledCode = uglify.uglify.gen_code(tree);
+	// Execute it
+	return eval(compiledCode).apply(null,globalValues);
+};
+
+exports.Sandbox = Sandbox;
+
+})();
\ No newline at end of file
diff --git a/js/WikiTextRenderer.js b/js/WikiTextRenderer.js
index 61dd7f051..8f67e5232 100644
--- a/js/WikiTextRenderer.js
+++ b/js/WikiTextRenderer.js
@@ -129,7 +129,19 @@ WikiTextRenderer.prototype.executeMacro = function(macroNode,title) {
 	var macroInfo = WikiTextRenderer.macros[macroNode.name];
 	macroNode.output = [];
 	if(macroInfo) {
-		macroInfo.handler.call(this,macroNode,title);
+		var args;
+		if(macroInfo.argOptions) {
+			var argOptions = {
+				globals: {
+					title: title
+				}
+			};
+			for(var g in macroInfo.argOptions) {
+				argOptions[g] = macroInfo.argOptions[g];
+			}
+			args = new ArgParser(macroNode.params,argOptions);
+		}
+		macroInfo.handler.call(this,macroNode,args,title);
 	} else {
 		macroNode.output.push({type: "text", value: "Unknown macro " + macroNode.name});
 	}
@@ -139,18 +151,25 @@ WikiTextRenderer.versionTiddlyWiki = "2.6.5";
 
 WikiTextRenderer.macros = {
 	allTags: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	br: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 			macroNode.output.push({type: "br"});
 		}
 	},
+	echo: {
+		argOptions: {defaultName: "anon"},
+		handler: function(macroNode,args,title) {
+			var globals = {title: title};
+			macroNode.output.push({type: "text", value: args.byPos[0].v});
+		}	
+	},
 	timeline: {
-		handler: function(macroNode,title) {
-			var args = new ArgParser(macroNode.params,{defaultName:"anon"}),
-				anonByPos = args.getValuesByName("anon",[]),
+		argOptions: {defaultName:"anon"},
+		handler: function(macroNode,args,title) {
+			var anonByPos = args.getValuesByName("anon",[]),
 				field = anonByPos[0] || "modified",
 				limit = anonByPos[1] || null,
 				dateformat = anonByPos[2] || "DD MMM YYYY",
@@ -214,9 +233,9 @@ WikiTextRenderer.macros = {
 		}
 	},
 	list: {
-		handler: function(macroNode,title) {
-			var args = new ArgParser(macroNode.params,{defaultName:"type"}),
-				type = args.getValueByName("type","all"),
+		argOptions: {defaultName:"type"},
+		handler: function(macroNode,args,title) {
+			var type = args.getValueByName("type","all"),
 				template = args.getValueByName("template",null),
 				templateType = "text/x-tiddlywiki", templateText = "<<view title link>>",
 				emptyMessage = args.getValueByName("emptyMessage",null);
@@ -275,29 +294,29 @@ WikiTextRenderer.macros = {
 		}
 	},
 	slider: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	tabs: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	tag: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	tagging: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	tags: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 		}
 	},
 	tiddler: {
-		handler: function(macroNode,title) {
-			var args = new ArgParser(macroNode.params,{defaultName:"name",cascadeDefaults:true}),
-				targetTitle = args.getValueByName("name",null),
+		argOptions: {defaultName:"name",cascadeDefaults:true},
+		handler: function(macroNode,args,title) {
+			var targetTitle = args.getValueByName("name",null),
 				withTokens = args.getValuesByName("with",[]),
 				tiddler = this.store.getTiddler(targetTitle),
 				text = this.store.getTiddlerText(targetTitle,""),
@@ -312,22 +331,22 @@ WikiTextRenderer.macros = {
 		}
 	},
 	today: {
-		handler: function(macroNode,title) {
+		argOptions: {noNames:true},
+		handler: function(macroNode,args,title) {
 			var now = new Date(),
-				args = new ArgParser(macroNode.params,{noNames:true}),
 				value = args.byPos[0] ? utils.formatDateString(now,args.byPos[0].v) : now.toLocaleString();
 			macroNode.output.push({type: "text", value: value});
 		}
 	},
 	version: {
-		handler: function(macroNode,title) {
+		handler: function(macroNode,args,title) {
 			macroNode.output.push({type: "text", value: WikiTextRenderer.versionTiddlyWiki});
 		}
 	},
 	view: {
-		handler: function(macroNode,title) {
-			var args = new ArgParser(macroNode.params,{noNames:true}),
-				field = args.byPos[0] ? args.byPos[0].v : null,
+		argOptions: {noNames:true},
+		handler: function(macroNode,args,title) {
+			var field = args.byPos[0] ? args.byPos[0].v : null,
 				format = args.byPos[1] ? args.byPos[1].v : "text",
 				tiddler = this.store.getTiddler(title),
 				value = tiddler ? tiddler.fields[field] : null;
diff --git a/tiddlywiki5/BootLoader.js b/tiddlywiki5/BootLoader.js
index 2db599857..15ceede96 100644
--- a/tiddlywiki5/BootLoader.js
+++ b/tiddlywiki5/BootLoader.js
@@ -7,7 +7,6 @@
 Given the absolute path of a srcModule, and a relative reference to a dstModule, return the fully resolved module name
 */
 function resolveModuleName(srcModule,dstModule) {
-console.log("Resolving " + dstModule + " in the context of " + srcModule);
 	var src = srcModule.split("/"),
 		dst = dstModule.split("/"),
 		c;
diff --git a/tiddlywiki5/tiddlers/HelloThere.tid b/tiddlywiki5/tiddlers/HelloThere.tid
index 8b1ec1b1f..c2260fc1e 100644
--- a/tiddlywiki5/tiddlers/HelloThere.tid
+++ b/tiddlywiki5/tiddlers/HelloThere.tid
@@ -8,3 +8,5 @@ TiddlyWiki is a unique [[wiki|WikiWikiWeb]] that people [[love using|Raves]] to
 TiddlyWiki is written in [[HTML]], [[CSS]] and JavaScript to run on any reasonably modern [[browser|Browsers]] without needing any ServerSide logic. It allows anyone to create personal SelfContained hypertext documents that can be published to a WebServer, sent by email, stored in a DropBox or kept on a USB thumb drive to make a WikiOnAStick. Because it doesn't need to be installed and configured it makes a great GuerillaWiki. This is revision <<version>> of TiddlyWiki, and is published under an OpenSourceLicense.
 
 Unlike most wikis, TiddlyWiki doesn't directly support group collaboration; it is a wiki in the sense of elevating linking be a part of the punctuation of writing. You can easily publish a TiddlyWiki you have created by placing the single file on a web server (for instance the homepage hosting provided by many ISPs). If you need full  group collaboration features, there are several HostedOptions to choose from.
+
+<<echo {{2+2 /* something */ - 3 * 17 + title + tiddlywiki + out.length}}>>
diff --git a/tiddlywiki5/tiddlywiki5.recipe b/tiddlywiki5/tiddlywiki5.recipe
index 2e179fec8..db48a47ff 100644
--- a/tiddlywiki5/tiddlywiki5.recipe
+++ b/tiddlywiki5/tiddlywiki5.recipe
@@ -9,6 +9,7 @@ recipe: tiddlers/split.recipe
 
 jslib: ../test/tiddlywiki.2.6.5/source/tiddlywiki/jquery/jquery.js
 
+jsmodule: ../js/Sandbox.js
 jsmodule: ../js/ArgParser.js
 jsmodule: ../js/FileRetriever.js
 jsmodule: ../js/Utils.js