A natural history museum.
We bought (used) a hutch with glass front doors to house the kids' finds. The museum includes: skeletons (fox skull, deer skull and spinal column, piranha skull, bird skeletons and needle fish jaw). There are also bird nests, snake skins, large shells - fresh and salt water, fossils in limestone, horseshoe crab bodies, feathers, dried insects and various insect nests and cocoons. Most things are labeled as to what they are, where they were found, etc. The hutch is really not large enough to properly display all of it, but it is enough.
The functional name is "the drawing room". Not in the victorian sense, but in the kid's paint, markers, and crafts sense.
There is also an old table and four chairs and assorted items inherited from inlaws that we don't know what to do with and I hope we can get rid of soon (a guitar, organ, and 3 small tables - No one has any musical inclination).
The only ones who eat there are the cats.
Definately the most dysfunctional room in the house.