Flashninjaclan.com has a very creative game titled Asteroid’s Revenge.
In this version of Asteroids you pilot an asteroid and must avoid a field of starships that fire at you. When your asteroid is hit, it shrinks in size.
From Wikipedia, re: Asteroids:
Asteroids was inspired, in a roundabout way, by the seminal Spacewar!, the first computer-based video game. [...]
Asteroid’s Revenge