I have found a super cool site on the paris train system website (
Paris Visite : carte Musées et Monument) that describes (in french, use google or altavista if you must translate it) a card that allows admission into 70 museums and monuments in and around Paris.
I think it is perfect for our upcoming trip. I would say to buy the 5-day pass. The only negative is that it doesn't include the Eiffel Tower. :( Oh well.
If you look around the site you'll also find the great multiday passes for trips on the Metro. This just about covers our transportation and entertainment needs.
I would look around the site but I'm trapped in Mexico with a HORRIBLE connection. :(