The Ketchup Experiment! Kid friendly site with lots of neat experiments! It has one that makes a rocket out of a film canister, which would be good for an grade space unit, but it has to many kid friendly expiriments. Great site for any science teacher.
If you're trying to freak someone out with crazy Halloween food, I can tell you confidently that you HAVE to try this Jello Worm recipe! It's the perfect addition to your Halloween parties for kids AND adults.