If you have children who love LEGO, you MUST visit LEGOLAND. My husb and i took our 10yr old son and we visited twice. You cannot see all this park in one day as it is huge. We did the Lego park on the first day and then the Aquarium and the Waterpark on the second. The Aquarium is easily done in a couple of hours but the waterpark is also huge and once you're children are inside, they won't want to come out. Loved everything about this park. It is a long drive out of Anaheim but well worth it.
If you're between the ages of 4 and 8, this place is heaven. The rides are - mostly - tame and targeted at kids, and there's plenty of Lego building blocks and models to keep you entertained.
We didn't have time to go to the aquarium or water park, but they look cool, especially if the weather was hot.
We saw some people in Legoland itself without kids, which was a head-scratcher. There's not much for adults here, it's really all about the kids.
It's also heavy on the marketing tie-ins. I dare you to leave Legoland without buying at least one Lego kit. It's impossible. Luckily your kids will have plenty to chose from and will be very happy that Legoland has a great collection of cool and hard-to-find Lego kits.