It was probably similar to how he decorated his classroom, which (in the films) was quite entertaining, here's a picture that I've edited to point out some of the more interesting things.
So as you can see he definitely keeps some interesting things in his classroom, including whatever kind of skull that is in the upper left(ish) I've tried to find an image online that matches it but have failed. A lot of what can be seen in the windows were the skull is (the tooth and other mysterious objects) seem to be more personal decorating points rather than teaching points but the (what I've) called a Carpet in the bottom right is probably a object of interest for students as well as the cauldron.
Furthermore, the only actual picture I have been able to find of the actual interior of his office was this:
This seems to match the theme of the classroom pretty well containing some African Tribal masks, skulls on the shelf and a bunch of turbans in the corner (again I edited the picture to point these out).
Image sources: Behind the scenes: Defence Against the Dark Arts classroom - Pottermore that's the first picture, Defence Against the Dark Arts teacher's office - Harry Potter Wiki