Zyan Drench is a simple yet very entertaining brain teaser game developed using Zyan Communication Framework: http://zyan.com.de
Game board is a random picture of size 15x15. Start from the top-left corner of the board. Select a new color for the top-left pixel, and all adjacent pixels of the same color will be painted over with the new color. The goal is to drench the whole board with your own color.
Zyan Drench has several modes: play against Android phone (with adjustable skill level), play solo (classic single-player puzzle mode) and network game. It is completely ad-free and open source, hosted at https://drench.codeplex.com and https://github.com/yallie/drench.