mplsmike saidBest tip is to not go.
Good lord - you people are the crankiest people on the planet.
Monochrome, ignore the two bitchy queens before - they just want to seem funny and clever by saying "Oh yeah, Cincinnati sucks!". It's not a horrendous place. Nothing fantastic, but if you listen to people like these two, you'd think it's Nazi Germany!
There actually is a Contemporary Arts Center right in downtown; 6th and some place. The Aronoff Center is right downtown, and is more events based. The schedule for Cincinnati Playhouse in the Park should have kicked in by now. The Cincinnati Musuem of Art is, I believe, right downtown, and Union Terminal has the Cincinnati Museum Center; the Terminal itself is and an old train station they converted over. It's fairly cool.
Other than that, the Ochestra is supposed to be good and Music Hall is right in downtown.
If you're looking for architecture, head to Mt. Adams/Eden Park. The one thing that surprises people is how hilly it is, and that's the area where some of the more interesting homes are. The place is right near downtown, off i-71. Music Hall is actually a beautiful building, and if you're looking for more modern, the skyline in Cincinnati is surprisingly nice coming in from the Kentucky side. The Roebling Bridge connecting Covington to downtown is something like 160 years old. Fountain Square downtown has the iconic statue you see on a lot of a sporting event videos.
But by all means, if you're going, don't listen to the crank asses who say "Duh,Cincinnati sucks". It's not heaven, it's not Camelot, but my lord, people just need to relax. Cincinnati's a mid-sized midwestern town. There are plenty worse places. Good luck!