Lil’bot, the little robot that could, is a low-cost, open-source, Arduino-compatible balancing robot. It is ideal for learning to program, hacking and, of course, entertainment. Lil'bot can express some artificial emotions through an emoticon-like LED display called “EmoShield”.
Source: Chris Hakim
A video of Lil’Bot running in a square figure. It demonstrates its ability to stop, go and turn.