$.widget("ui.round_button", {
   // default options
   options: {
     option1: "defaultValue",
     hidden: true
   },

   _create: function() {
	   	this.element
			.addClass( "rb-basic" )			
			.hover(function() {
				$(this).stop();				
				$( this ).addClass("rb-hover", 1); 
				$(this).css("opacity:1");
			}
			, function() {
					$(this).stop();
					$( this ).removeClass( "rb-hover", 1 );
					$(this).css("opacity:.7");
			})
			.click( function(){
				window.location.href=$(this).children("a").attr("href");
			})
		
   },
   value: function() {
     // calculate some value and return it
     return this._calculate();
   },
   length: function() {
     return this._someOtherValue();
   },
   destroy: function() {
       $.Widget.prototype.destroy.apply(this, arguments); // default destroy
        // now do other stuff particular to this widget
   }
 });