Interval -- Magic?

gistfile1.scala

   object interval {

      val list = collection.mutable.Map[ Class[_], Double ]()

      /** Runs a block at a given interval */
      def apply(t:Double, executeNow:Boolean=true)( block : =>Unit) {
         val klass = (()=>{block}).getClass
         if(list.isDefinedAt(klass)) {
            val lastTime = list(klass)
            if(util.getSeconds - lastTime >= t) {
               block
               list(klass) = util.getSeconds
            }
         }
         else {
            list( klass ) = util.getSeconds
            if(executeNow) block
         }
      }
   }

In your update loop, put:

interval(0.5) {
println("foo")
}

to print "foo" every 0.5s.