Originally Posted by Jilz
Since you're always tired when you arrive, and its hard to get much done, my suggestion would be to go directly to the TGV (it's at the airport) and go to the south of France. It's about 2 1/2 hours, and you don't usually get that much done on your arrival day, anyway. Spend a couple of days in Avignon or Aix, or go all the way to a Mediterranean town.
Avignon might provide some entertainment for the kids. The train ride is closer to 3 1/2 hours from Paris (about 500 miles). Whether you would leave from the airport or not there are things to see and do. You can tour the castle, former home to numerous Popes. Le Pont St Bénezet is right there. Horseback riding or a river cruise are other possibilities. Also nearby is Pont du Gard, a Roman aquaduct, that was used in a Volkswagen commercial.
Many good suggestions in the various posts. If you go to Eurodisney one day is probably enougn time. Stay late for the fireworks.