I still haven't made it over to the American Dream in East Rutherford to check it out.  I want to try the indoor skiing. I have heard plenty of good things about it.

The Dreamworks Indoor Water Park looks really cool too. It has just been announced that the official opening date is March 19th!

According to NJ.com:

Visitors to the water park will be able to swirl through more than 40 water slides and 15 attractions themed after DreamWorks characters like Shrek, Kung Fu Panda and Madagascar. The water park has a lazy river, a children’s play area and the world’s largest indoor wave pool -- at 1.5 acres. The park itself is also record-setting -- it’s the largest indoor water park in the country.