Hello, I am from Minnesota and have a couple ideas for you.....MOA is really fun but really big. Check out the website or a brochure because you have to 'plan' what you want to do...you will never get everywhere. My opinion is that there are no really good deals/sales there, so you are really going for the experience or the Nickolodean theme park. I find much better bargains at the smaller malls in town.
The Minnesota Zoo is a great zoo, but can be expensive. ($16 for adult/$10 for kids 3-12) Ask at your hotel for discount coupons or look for deals. There is Como Zoo in St Paul (probably about 20 mins away, depending on where you are staying) that is nice and they just ask for a 'donation'. They both have websites you can google for tips and ideas.
Other ideas are to catch a Twins or Vikings game, depending on when you will be here. There is also a wonderful Science Museum, also in St Paul, that is a great place for kids (
Science Museum of Minnesota - Minnesota's Favorite Museum). They have a great 'hands on' kids area. Are you coming up this summer or in the fall? There is the State Fair or a really great Renaissance Fair in late Aug/Sept too, if you are into that kind of thing.