How's this for a great geeky project? For knitters young and old, loxosceles.org has published directions to Knit Your Own Bacteria. I don't know anything about knitting but the project doesn't look too difficult even for younger crafty bio-fans. The non-crafty can always buy their favorite plush Giant Microbes from ThinkGeek or various other places on the web. Google is practically infected with them! (And all the readers groan and remove this link from their favorite bookmarks)
Thanks to Julie Knapp at the Homeschool Diner (see link at left) for turning me on to this one!