I've chosen the "Symet" to be your first "warm-up" project. Symet is one of the simplest BEAM robots that you can build. It uses only a few easy to find parts and it is a good introduction to a solar-powered independent creature. Another great advantage is that there is a site with complete and detailed instructions on how to build it so you can refer to it as well. This project only takes a few hours at the most, so it should be up and running by next Thursday.
Check the list of parts on the link above and get them at any of the 3 or 4 Radio Shacks in town.
The "Nice to have" items are for those of you who have more than a passing interest in how electric or electronic things work.