I've always been fascinated by maps, and I like contributing to open projects but I don't want to do the programming. I find it extremely satisfying to see my data incorporated into the main map week by week. I prefer JOSM to the applet.
I'm mostly doing bits of Edinburgh city centre as they take my fancy, wandering up the middle of quiet streets with a Garmin GPS 60. I did a bit of Leith, a good chunk near the West End, and assorted sections of the South Side.
I've also done about 60% of Bishopton, Renfrewshire. Next time I get over there I'll finish it.
When the weather turns I will get out on my bike and be more ambitious.