How about this?

    def timeIt(numIters: Int)(f :=> Unit): Long = {
      val start = System.currentTimeMillis
      var i = 0
      while (i < numIters) {
        f
        i += 1
      }
    }

This way, you get rid of the TimesInt class and the implicits. We need to be very careful about implicits, since they make the code much harder to understand.