The distance from Indianapolis, IN to Pittsburgh, PA is 360 miles. By car this would take 5 hours and 37 minutes, traffic dependent.
Another option would be to fly, however, you would need to change planes along the way, which means the total travel time does not end up being an awful lot less, usually around 3 and a half to four and a half hours.
If you fancy a road trip, one of the places you'll pass along the way is Columbus, Ohio. There's plenty to do here, it's actually the 15th largest city in the States - right behind San Francisco!
One thing you couldn't pass through Columbus without trying is the Thurman Burger, which is essentially a GIANT burger, complete with a ham sandwich on top. It's mammoth and a local... Err, delicacy.