Boe Bots can be a bit pricey, certainly not something you will let the kids take home after camp is over. How about some BEAM bot kits. They run around $25, check out the hobbyengineering.com web site. Cheap enough for them to have something to experiment with after camp.

Contact companies like Freescale about evaluation boards they sell to promote their micorprocessor. They come with C compilers. The 68HC08QT4 was around $30 last time I looked.

BC