Flick Boomerang - Small thin plastic boomerangs. They work great!

A great indoor 'rang!

These are amazing little flyers. The moderate forward sweep allows you to control mid-flight lay over just enough to fly inside without high ceilings. By modifying the throw speed, release angle and spin, you can really get some cool flights... even with very little arm strength. You can even experiment with adding (very light) weights to the wing tips. An outstanding value; I have a stack of these for turning friends on to the sport.