Wizard's library or study. If you look closely, you can see that this consists of multiple tiles, so that they can be reassembled to form different rooms. Specifically, there are four floor sections and two walls, all of which come apart and can be rearranged. The door can be taken out to create an open doorway or passage.
The fire (and firewood) is sculpted from apoxy sculpt. So is the fur rug. Bookshelves are popsicle sticks and the books are popsicle stick pieces and bits of index cards. I should've painted the wood darker on the shelves. The book is a Warhammer model I think, painted in acrylic. The door is pieces of popsicle sticks. The chain is small jewelry chain.
I've been wanting to do something similar to this myself using poly clay. =3 Seeing it done rather motivates me.
For the floor and walls, I used some molds from [link]
They're very useful, but pretty expensive unless you're planning on using them a lot.