I don't know what actual tourists do there, but I lived near Fort Knox for 13 years, so I'll try to think of some stuff (and my sister and brother live in Louisville...I'll ask them for some ideas).
In Lexington, there's the Horse Park, Keeneland (horse race track), Rupp Arena (although I don't know if they have tours or if that'd even be worth it unless you're a huge UK fan & since you're an Aggie I'll assume you aren't).
In Louisville there's the science center (my sister's kids favorite), the zoo (although the train there recently jumped the tracks and hurt some folks..maybe not such a great idea!), Churchill Downs, the Louisville Slugger factory, Six Flags (Kentucky Kingdom).
If you're near Fort Knox (about 45 miles south of Louisville) and are interested in history/wars at all I highly recommend the Patton Museum. It's technically on base, but is open to civilians also.
There's Mammoth Cave, the bourbon trail (a bunch of distilleries), beautiful scenice highways, and Cincinnati's only a few hours away (2-2 1/2 from Louisville/Lexington)... It's really not that far to most places in KY. What kind of stuff are you interested in? Are there kids going? When are you going?
I'll ask my sister and brother what else they can think of, since I haven't lived there since 2000.
Oh yeah, and there's Abe Lincoln stuff, as he was born in KY. If you check out KY's website and click on the regions you're interested in (under Discover Kentucky), that should help...
http://www.kentuckytourism.com/Edit: Forgot about Corvettes...they are made in Bowling Green. Not sure what all you get to see on the tour, but if you like vettes then it's probably for you!
[This message has been edited by jamaeusa (edited 6/20/2009 12:12p).]