var Test = new Class({    
    Aspect:'Test',
    initialize:function(cycle){
        
        for(var c=0;c<cycle;c++)
        for(var i=0,max=10000;i<max;i++){        
            //donothing        
        }
    }
});

Profile.addEvent('trace', function(x){console.log(JSON.encode(x))});

var x = new Test(1);//{"description":"Test","uniqueID":4,"name":"initialize","params":{"0":1},"callno":1,"executionTime":1}

var y = new Test(1000);//{"description":"Test","uniqueID":5,"name":"initialize","params":{"0":1000},"callno":2,"executionTime":34}

<script src="https://raw.github.com/keeto/mootools-pattern-mutators/master/Source/Class.PatternMutators.js"></script>
<script src="https://raw.github.com/gist/1278659/64ee9462dec56a74e0db9ee3f01db3c62f9dd957/kenta.AOP.js"></script>
<script src="https://raw.github.com/gist/1275736/24f145a45252400ce2fd4fe1e6ef66071ba85cfb/kenta.AOP.Profile.js"></script>
<p>
    where <dl>
    <dt>description</dt><dd>Is the string you've associated to the Aspect property</dd>
    <dt>name</dt><dd>Is the name of your method</dd>
    <dt>uniqueID</dt><dd>is an ID unique per instance</dd>
    <dt>params</dt><dd>Are the parameter passed to your method</dd>
    <dt>callNo</dt><dd>Is the trace order number</dd>
    <dt>executionTime</dt><dd>Is the execution time of your method(ms)</dd>
    </dl>

*{
    padding:0;margin:0;
    font-family:'Trebuchet MS',Verdana;
    font-variant:small-caps;
    background-color:whitesmoke;
}
dt{
    color:steelblue;
    padding-left:1em;
font-weight:bold;
}
dd{
 padding-left:2em;
}

jsFiddle