Built in 1776 on the site of a medieval castle. Unfortunately, you could only get in to see its huge collection of manuscripts if you were in a group.
Kalocsa is situated on Hungary's Great Plain and is the center of the country's paprika-producing region. It's also famous for its flowery handiwork, which was one of the main reasons I wanted to visit. They say this town is a popular stop for cruise boats on the Danube, but quite frankly, I can't even imagine what tourists do there as the place isn't really set up for visitors. There were only two of us, so we couldn't tour the palace; the famous cathedral was closed for extensive restoration; the famed Paprika Museum was tiny and dingy; the synagogue was closed and decrepit; the House of Folk Arts could have been nice but was quite dark; and I only found one place selling the famous Kalocsa embroidery, and quite frankly, Budapest has better examples of it.
In short, I wouldn't recommend Kalocsa as a tourist destination, unless you have absolutely nothing else to do. I did get a few pictures from there to make it worth the two-hour drive, so it wasn't a total disappointment.