diff --git a/lib/jasmine-0.10.1.js b/lib/jasmine-0.10.1.js
index 0f6c015..f9bd7d6 100644
--- a/lib/jasmine-0.10.1.js
+++ b/lib/jasmine-0.10.1.js
@@ -1001,10 +1001,11 @@ jasmine.JsApiReporter.prototype.summarizeResult_ = function(result){
  * @param actual
  * @param {jasmine.Spec} spec
  */
-jasmine.Matchers = function(env, actual, spec) {
+jasmine.Matchers = function(env, actual, spec, opt_isNot) {
   this.env = env;
   this.actual = actual;
   this.spec = spec;
+  this.isNot = opt_isNot || false;
   this.reportWasCalled_ = false;
 };
 
@@ -1014,8 +1015,12 @@ jasmine.Matchers.pp = function(str) {
 
 /** @deprecated */
 jasmine.Matchers.prototype.report = function(result, failing_message, details) {
-//  todo first: report deprecation warning [xw]
-//  todo later: throw new Error("As of jasmine 0.xx, custom matchers must be implemented differently -- please see jasmine docs");
+  // todo: report a deprecation warning [xw]
+
+  if (this.isNot) {
+    throw new Error("As of jasmine 0.11, custom matchers must be implemented differently -- please see jasmine docs");
+  }
+  
   this.reportWasCalled_ = true;
   var expectationResult = new jasmine.ExpectationResult({
     passed: result,
@@ -1038,15 +1043,23 @@ jasmine.Matchers.matcherFn_ = function(matcherName, matcherFunction) {
   return function() {
     var matcherArgs = jasmine.util.argsToArray(arguments);
     var result = matcherFunction.apply(this, arguments);
+
+    if (this.isNot) {
+      result = !result;
+    }
+
     if (this.reportWasCalled_) return result;
 
     var message;
     if (!result) {
       if (this.message) {
         message = this.message.apply(this, arguments);
+        if (jasmine.isArray_(message)) {
+          message = message[this.isNot ? 1 : 0];
+        }
       } else {
         var englishyPredicate = matcherName.replace(/[A-Z]/g, function(s) { return ' ' + s.toLowerCase(); });
-        message = "Expected " + jasmine.pp(this.actual) + " " + englishyPredicate;
+        message = "Expected " + jasmine.pp(this.actual) + (this.isNot ? " not " : " ") + englishyPredicate;
         if (matcherArgs.length > 0) {
           for (var i = 0; i < matcherArgs.length; i++) {
             if (i > 0) message += ",";
@@ -1818,7 +1831,9 @@ jasmine.Spec.prototype.addMatcherResult = function(result) {
 };
 
 jasmine.Spec.prototype.expect = function(actual) {
-  return new (this.getMatchersClass_())(this.env, actual, this);
+  var positive = new (this.getMatchersClass_())(this.env, actual, this);
+  positive.not = new (this.getMatchersClass_())(this.env, actual, this, true);
+  return positive;
 };
 
 jasmine.Spec.prototype.waits = function(timeout) {
@@ -2257,5 +2272,5 @@ jasmine.version_= {
   "major": 0,
   "minor": 10,
   "build": 1,
-  "revision": 1267069453
+  "revision": 1267503060
   };