Hey Butch,
Sanibel/Captiva is nice, there is a lighthouse, piers, shelling, etc. The toll is 6 bucks though which is a ripoff if you ask me.
If you like to fish, there is Captain Tony's Fishing Adventures in Ft. Myers. It's not the best fishing charter, but it's cheap and you do catch fish, see dolphins, etc. I would recommend the front of the boat if you can get it. I think it is 60 bucks for a 6 hour charter (20-30 miles out), the downside is you are only 1 of potentially 100 people on that boat so it gets crowded, hence the front of the boat recommendation. Plus you only stay at each fishing spot for about 20-30 minutes before spending another 15 going to the next one. So you are only actually fishing about 1/2 the time. But seeing as how private charters are around 400-900 bucks for 4-8 hours, 60 bucks is steal in my book.
I'm sure there is other cool stuff there, but I usually go to Sanibel or Marco Island and do the family beach vacation thing so don't get a chance to do much other than that.
Hopefully there are some Ft. Myers natives on this site for you.