Minicraft, the game created by Minecraft man Markus "Notch" Persson in 48 hours last year, has been ported to Android devices. It's not an official port of the game, but has instead been (ahem) crafted by Folstad Consulting. The developer implemented touchscreen controls with optional keyboard controls for compatible devices.
If you missed Minicraft the first time around, it's essentially a miniaturized, 2D version of Minecraft. Though it lacks many features found in the bigger Minecraft, it does let you slay enemies, harvest resources and craft items. If you need some crafting on the go, you can download Minicraft for free from the Android Market.