Tetris for DragonRuby
DragonTT is a simple implementation of Tetris for DragonRuby.
Initially intended as a simple testbed to check out the toolkit, it turned into a stable, playable and even releasable game inside of a week.
So, that answers the question of how good DragonRuby is!
The source is available her on GitHub; you can find a playable HTML version right here and executables for other platforms over on itch.io