Updated April 8, 1999
The Exploratorium in San Francisco is one of the world's truly great, hands-on science museums for kids of all ages.
Of course they have a great web site as well. And, happy day, they just added a new Science Snack section on lactose intolerance!
Who else would have a science experiment that would allow kids to test milk with and without added lactase drops to see digestion in action?
Although it's pitched towards teachers as a class experiment for older kids, most adults would learn a lot from this page. There's a good history of how milk drinking spread around the world as well.
And, of course, you can go back and play at the rest of the site.