ok so we.....go to WDW!!!!
we
bought a membership to our local Science Center (AKA a Touch museum). it was $125 for a 1 yr family membership. The nice thing about this is since we live in Orlando, we also have access to the other Science Centers in nearby cities. At $15-$20 per adult or child this thing pays for itself in 2 - 3 visits and the kid learns stuff (us also).
check out this site
www.astc.org. you may be able to do this with children's museums also.
A cheesy thing we do sometimes, and this only works because the kid likes to eat new things, is go to a specialty or ethnic market and pick out something we've never tried before and go home and cook it. You can kill 2 hours in the market and then another hour or two making and eating whatever you've found. IF you have internet, doing the research about that country or ethnicity eats up a lot of time also. Just don't go on an empty stomach.