anything athletic works good. Like how to play tennis, the serve, the return, the backhand, bla bla bla. All very easy stuff to explain and it gives you a lot of body movement too so you aren't trapped just standing there with your hands on your side. Demonstration speeches should be where you get your best grade man. Just think of something. Hundreds of things out there. Sports stuff is pretty easy though. Act it out, or demonstrate it.