I have done some mapping on OpenStreetmap since 2009. One of my interests is Cycle networks since I found those to be incomplete in many locations. I've done some work on e.g.
Recently I have concentrated on the cycle networks around Stockholm:
I have tagged both of these as network=lcn for lack of better granularity in the OSM tags. "Regionalt cykelnät" (red signs) covers an area roughly 20 km from the city centre, while "Lokalt cykelnät" (green signs) constitutes short detours from that.
In addition I have mapped a few roads and paths near my summer house in Tiveden. The area around Årsta south of Stockholm where I live is already fairly complete, so my mapping there has concentrated on details such as buildings and house numbers.