Totally biased opinion: Indianapolis
The Good Stuff
Indianapolis Motor Speedway: Currently hosts Indycar road and oval races, Nascar, RedBull Air Race, a pretty decent Vintage Race and has hosted F1, Moto GP, and whatever the Tudor/ALMS series is called these days. There have been talks of adding lights to the track in order to host endurance races, but for now those are just talks (sigh).
Lucas Oil Raceway: Most famous for hosting The US Nationals every year (the Daytona 500 or Indy 500 of the 1/4 mile world) they also have a short oval track and have lower level drags and test/tunes all the time.
Putnam Park Raceway is very close for track days
It's also just a couple of hours from Mid-Ohio, Kentucky Speedway, Chicagoland, and dozens of dirt and pavement circle tracks if you like sprint cars, midgets, modifieds, Demolition Derbys, Montster Trucks, etc. The Corvette plant in Bowling Green is a nice day trip too. Or Churchill Downs if you prefer your Horsepower in more literal terms.
There are a couple of decent places to go offroading in vehicles, or ATVs/Dirtbikes.
Home to most of the NHRA and IndyCar teams if you'd be looking for a job, or you just like going on shop tours.
Has the usual autocross, rallycross, Cars and Coffee types of events
The Bad Stuff
We have this thing called winter where it tends to get cold and sometimes snowy. Thherefore, racing takes place between March (at the earliest) and October (at the latest), but we have the PRI show in Dec to break the winter monotony. Plenty of professional and semi professional sports teams too if you're into that.