We went to Great Wolf Lodge in Washington for Spring Break and had lots of fun. It is a huge resort and indoor swimpark with 3 pools, 2 hot tubs, 6 waterslides and a huge water play structure that dumps a gigantic bucket of water every 2 1/2 minutes.
They also have this interactive game called MagiQuest that the kids had a blast playing. The kids all got wands and instructions to find certain things around the hotel that come to life and speak to you. They ran around from floor to floor finding different enchanted objects and fighting interactive dragons and talking to pixies. It was fun for them and exhausting for me! There were about 500 other kids doing the same thing, and running from floor to floor was tiring, but good exercise, I guess. It's a great place for a family vacation, just avoid the crowds and don't go for spring break!