1. Dark Nebula is a great marble-em-up that's over too fast but only costs a dollar.
2. Anomaly Warzone Earth HD. Incredible port of the PC game, made better on touchscreens, but still with the insane amount of voiceovers and enjoyable reverse-tower-defense gameplay.
3. Stellar Escape is sort of like Canabalt, but maintains a more stable pace and causes your brain to short out trying to reflex your way through jump or slide or dive, or grab a rail or duck into a tube. It's excellent.
4. Edge (which you might remember from my iPhone review is delicious good fun.
5. Train Conductor 2: USA is a unique little thing that ticks all the right boxes for me. Varied gameplay, quickly escalating difficulty, score-driven challenge and brain-snapping action that's very well suited to the touchscreen.
6. Pinball Arcade from Farsight is the best pinball action on Android. Until those bastards at Zen release a non-Tegra version of Zen Pinball, at least.