I don't have any pressing orders right now, so I started a Positively Useless Project earlier this week. I finished it last night:
A stablemate scale stall and tackroom! They're two separate "rooms" so, should I get crazy in the future, I can add more stalls to it or rearrange. My building materials were balsa wood, craft sticks, and lots and lots of hot glue. The door actually slides, though it's a little rough. I haven't figured out how I want to make a latch yet, or do the feed/water buckets and suchlike.
These aren't completely useless; Janet Skybova of JS Custom Tack made a neato tack room diorama of her own that she uses for photos sometimes. That's what inspired me to make mine. You can check her Traditional scale diorama out at her website, http://www.jscustomtack.net/