At the entrance to the Andong Hahoe Village there is the Andong Mask Museum. For 2,000 won it's probably worth it to walk around and check out what they have for about an hour.
Not only do they have an extensive collection of Korean masks, but also masks from around the world.
I didn't think to take photos of it while I was there, but their American halloween mask section was quite amusing. Who knew the things we sell for $5.00 at the local pharmacy could be put on display in another country?