For those of you working with middle school or older children, I just found a website I had to share. It is the Serendip page at Bryn Mawr college. First of all their philosophy of science education mirrors mine :
SCIENCE IS AN EXPLORATION (AND FUN)
Click on K-12 for teachers link and you'll find Hands-on Activities for Teaching Biology. Although some experiments assume you have basic scientific equipment at your disposal (the first yeast experiment asks for test tubes), often you can make do with things around the house (old spice jars).
Right underneath is Off the Shelf Chemistry, which is "for high school students, using consumer products for experiments and not requiring a lab and specialized equipment."
Take a look around and hope you have some hands-on science fun!