In my holiday I mapped a much of Rennweg in Katschberg, Kärnten, Austria. I had to create my changes in JOSM offline because I had no access to the Internet there. Now I uploaded it (the changeset contained 3819 nodes...). It wasn't rendered yet at the time of writing.

I mapped the residential area of Interlaken in a rather non-usual way, because there was no Yahoo imagery available. First, a photo was taken from the Harder-Klum viewpoint (node-id: 392295497). Then, I could estimate where the residential area started.

I mapped all buildings in the town Born, the Netherlands.
Not everything is rendered yet, so if you look to it, try to use Osmarender.

I think this place is mapped very weird... (zoom in to level 17)