If you have little people you need to get a book of science experiments. This one is pretty good. We just spent a great weekend making volcanos, destroying things in the garage, soldering, stripping wires, diminishing the larder, and tackling goldilocks problems.
//embedr.flickr.com/assets/client-code.js
When was the last time you mixed home made iron filings with golden syrup?
Steven Milne 