Today we printed ATDT8675309's Cube Puzzle on Thingiverse, which consists of eighteen rods that assemble into a nice regular structure. Except that we failed at the assembly part! Maybe we're all thumbs, had too much coffee, aren't as clever as we thought we were, etc...
Thingiverse link: http://www.thingiverse.com/make:89371
Settings: Printed on a MakerBot Replicator Mini at Standard settings with raft, and layer height bumped up to .3mm.
UPDATE: ATDT8675309 has put up a video walkthrough of the solution to this puzzle. Thank you, that was very helpful! My difficulty was with keeping the pieces together on the first few steps; if you can get past that then the pieces fit together in a very regular way with of course the one different piece being able to slide in at the end. Here's a hint for keeping everything aligned at the beginning: put two of the pieces underneath the sides to keep the cross-pieces at the correct height until the puzzle starts being rigid. The puzzle fits together just right with perfect clearance, and stays together nicely after being assembled. Here's the assembled model: