We give Daytona Beach a visit whenever we are in the area. Grab a meal at one or the area restaurants or clubs, take a stroll on the Boardwalk, Pier or Beach. Drive down the beach during low tide or visit the lighthouse. Visit the Daytona Speedway for a tour if you are a NASCAR fan.
Cocoa Beach is nice also for a beach day. There is also a day casino cruise out of Port Canaveral if you're into that (Victory Casino Cruise). They sail outside the 3 mile limit then the casino opens. It's a bit of a party cruise with many people (ourselves included) going for the boat ride, scenery, drinks and music etc. Groupon and TravelZoo usually have some great prices.
In the Kissimmee area, we give a big thumbs up for the Airboat tours. See some of the local wildlife up close and zip across the lake at full speed in a 500HP airboat. We used Boggy Creek Airboats on our last visit and had loads of fun (there are several other operators in the area also) Check Groupon or TravelZoo for Specials. We took the hour tour and wish we had booked the longer one, it was over all too soon. To see more wildlife, the early morning is best. If your looking to see some big gators, they offer after dark tours.
iFly indoor skydiving on International drive was a ton of fun also (found a great deal on Groupon for our last visit) This is a short activity, allow 1.5 - 2 hours for preflight training and your group to complete there flights. Tip: it's worth the extra $10 when you check in for the "High Flight"
There are several themed Dinner theaters in the area, Medieval Times, Pirates, Capones. They can be a nice way to have supper and round out your adult day. The shows can be a little cheesy but a lot of fun after a few adult beverages.
There is also a couple of Senor Frogs in the Orlando area that can get pretty lively in the evening. One is on International drive near the new Orlando Eye
I always wanted to try Flyboarding or Hoverboarding but never got up the courage to try, but it's offered at Lake Fairview (off Orange Blossom Trail). Looks like a riot if you're the adventurous type. Again, check Groupon for good specials.