We took a bus (public transport!) to Thirumayam Fort, about 35 kilometers from the town where my parents live. The fort is only about 300 years old (it's built on the remnants on an earlier fort), but is impressively located and comes with a rich history. In particular, in the 1800s, it was the stronghold of Kattabomman, one of the first Indian chiefs to resist the British (he lost).
The kids didn't care for any of the history, of course. But they appreciated the day trip to something other than a temple.