[JesseK]

Print snowflakes. Even the simplest one from Thingiverse will do. Print them and tweak your printer settings until the snowflakes are perfect. They take ~12 minutes each and mimic complex flat objects similar to what could be done on a robot.

I've fine-tuned my printer to get rid of issues with ooze, infill, extrusion speed, and even how Slic3r calculates its infill runs. It also produced something that looks great on a Christmas tree or stuck to a window. A hobby knife helps to clean up the 'bad' ones so they look good from a distance.

When you get frustrated, the Owl figurine from Thingiverse is a good print even for an out-of-tune printer. Unlike many other prints, it does well when scaled down to 50%. It's also a good conversation starter when put on a desk at work.