We had a great time on our Christmas trip on an airboat ride. We booked through Wild Willy's Airboats in St. Cloud and it was soooo much fun

. An awesome relaxing afternoon that turned out to be one of the highlights of our trip. We paired it with a morning at Gatorland and it was a perfect accompaniment. You can check out the photos and write up from our "gator day" in my trip report (see the link in my signature).
http://www.wildwillysairboattours.com/
We are visiting Showcase of Citrus in August on one of our "down days". There's currently a Groupon offer running which gives you half price admission on their Monster Truck ride through the orange groves, and a separate offer that give you a $20 voucher for $10 that you can use on food and gifts at their orchard store.
http://www.groupon.com/deals/showcase-of-citrus-2
Mini golf is fun. Mighty Jungle in Kissimmee is offering unlimited mini golf for two plus ice cream for $12:
http://www.groupon.com/deals/mighty-jungle-golf-adventure
We have also golfed at Congo River, Pirates Cove, Hawaiian Rumble, Gator Golf, and Volcano Island. Various discounts and offers can be found at each.
Other places we have enjoyed are the Titanic exhibit, the outlet malls, and the Florida Mall (love the M&M store!).