VimTouch (GitHub: momodalo / vimtouch, License: Apache 2.0) by David Tao is an open source port of Vim to Android devices. I currently have Gingerbread and Jelly Bean devices, and it runs on all of them.
The app launches with a menu of commonly used shortcuts, and the standard Android icons for saving files and a popup menu. A
~/.vimrc file is supported, and so are tabs and windows. Tapping windows and tabs works as expected, as does Vim's standard file management and navigation commands. Coloured syntax highlighting is enabled by default.
The Preferences menu allows the font size to be changed -- the default is a little small for some devices -- and there are various options for gestures, the escape key, and keyboard behaviour. I tested it with a Bluetooth keyboard and everything worked as expected.
It's similar to Vim for iOS, but it works better with a hardware keyboard. It's worth checking both out if you have access to an Android or iOS device.