Hexbugs are little battery powered plastic bugs which scuttle along on their flexible plastic legs, driven along by a small internal vibrating motor.
You can pick up an individual Hexbug quite cheaply from retailers such as Amazon and specialist toy retailers such as Toys R Us and The Entertainer. The people behind Hexbugs also do kits with bugs and tracks for them to travel along. The Hexbug V2 has additional top bristles to allow it to travel through tubes.
Hexbugs are in effect a commercial version of the home made bristlebot.
Bristlebots can be quite easily be made at home. The Evil Mad Scientist web site has a comprehensive step by step guide to creating one from a toothbrush, a coin cell battery, a double sided sticky pad, and the vibration motor from an old pager or mobile phone.
There are web pages and videos out there showing other home made bristlebots, including some made with much larger brush heads than a toothbrush.
Below are YouTube videos demonstrating the construction of two types of bristlebot.
Bristlebot made using a toothbrush
Video by Kalandar Suhail
Bristlebot made using a scrubbing brush
Video by Junkyard – Origin of Creativity