There's a cool history museum in downtown Orlando, and some art museums just north of downtown.
The Leu Botanical Gardens are also nice, as is the gardens at Bok Tower in nearby Lake Wales.
There's a small aviation museum out in Polk County right on I-4 that's supposed to be worth a visit.
If you like the outdoors, there are plenty of opportunities around for kayaking, snorkeling, tubing, hiking, airboat rides, surfing lessons, and such.
If you don't mind the drive, St. Augustine is the oldest city in the country and has a nice historical section, including a cool fort.
I know you're not into zoos, but the Brevard Zoo's treetop trek zipline/ropes course has become the new must-visit attraction whenever we have company in town.
Go visit Orlando Brewing if you like beer, or any of the numerous craft beer bars (World of Beer, Redlight Redlight, House of Beer).
Want to play laser tag with military-grade laser simulation weapons? Hard Knocks in Oviedo has you covered.
Go indoor skydiving. Or real skydiving.
Go on a horseback riding trek at Forever Florida.
You also didn't say anything about Universal Studios, so I'm going to recommend that
I'll post back as I think of more to do.