Not sure if these run on an Android Phone but they certainly run like hot sex on my 10.2" 2.2 Android Tablet:
The
Angry Birds games (Regular, Rio and Seasons)
Radiant Lite (superb touchscreen retro-style version of Space Invaders)
Bubble Blast 2 (sexy pop-the-bubbles puzzler)
Fruit Slice (wicked cool chop-em-up. Fast hands needed!

)
Reversi Free (Dude, it's REVERSI! What more is there to say? The wife loves owning me on it.

)
Duck Hunt. (Nintendo favourite, but sexier. As you finger the ducks instead of shooting your load into their mouth.)
Jewels. (It's Bejewelled.
Almost as good as Popcaps' original.Pity it's not on Android yet (I think?))

All games are free. Put your wallet away.
I've not long gotten my pad so I'm still collecting apps. There are some sweet ones like the Comic Book Reader that also downloads free comics (not pirate ones you tea-leaf!) and even fluff stuff for the kids like MagicMarker. An app that lets you draw with fluorescent neon markers all over everything. It's great in the dark to do fireworks!

Freestyler: A customer that's too hard to please, complains all the time and wants everything for next to nothing.