K.P.
I second Angela B's suggestion. Williamsburg (depending on which side of Richmond you are) is a good day trip (45 minutes give or take a bit). Busch Gardens/Water Country (and you can get the Fun Card/Sizzler for the entire summer 64.99 for each person 3+ for Busch). Colonial Williamsburg is cool too. My only suggestion is go before the tourists get there. (Generally by 4th of July. Make it a long weekend before school gets out.
Virginia Beach is also a good selection. There are so many things to do (both free and cheap) in the Hampton Roads area.
Either place would be great for either scenario. Contact me directly and I can give you some additional suggestions for things to do in the area. (I don't want this to be miles long of things to do) :)