Korat (Khorat), is also known as Nakhon Ratchasima. It is the "Gateway to Issan", which is to say it is the first major city you enter as you explore the Northeast. The Air Force has a big base there, so you see lots of soldiers, but otherwise, it is a typical large provincial capitol. There isn't a whole lot to see in the city itself, but nearby you can see the Khmer ruins at Phimai, and you can also make day trips to Phanom Rung. There's probably more to do here, and I just needed to get out more.
The central area of the city is surrounded by a moat and/or walls. On one side there is a park, which has this shrine dedicated to Thao Suranari (a sort of Thai folk heroine). At night, it sort of becomes like a carnival, and there are snacks you can eat, and there is a often little drama performances put on (can't understand it though).
Prasat Phimai National Historic Park is located about an hour away from Khorat. It is a small park, but it is worth seeing. The temples are Khmer style, and slightly older than the ones at Angkor Wat.
This temple is different from others in Thailand in that it doesn't seem to have bee npurposely destroyed by invading armies. Instead, it has simply fallen apart from extreme age.
The park isn't large, and you could probably explore most of it in an hour or less. Nearby is a very large banyan tree (not in this picture) where Thai people like to have picnics.
I would almost say that it is worth a trip to Khorat just to visit Phimai. Staying overnight in Phimai is also an option, and it seemed pretty quiet and laid-back.