Print maps, draw on them, scan them back in and help OpenStreetMap improve its coverage of local points of interests and street detail. Walking Papers is a product of Stamen Design's Michal Migurski.
See below to make your own printed map.
OpenStreetMap is a wiki-style map of the world that anyone can edit. In some places, participants are creating the first freely-available maps by GPS survey. In other places, such as the United States, basic roads exist, but lack local detail: locations of traffic signals, ATMs, cafés, schools, parks, and shops. What such partially-mapped places need is not more GPS traces, but additional knowledge about what exists on and around the street. Walking Papers is made to help you easily create printed maps, mark them with things you know, and then share that knowledge with OpenStreetMap.
To get started, search for a town or city you know, then pan and zoom the map to an exact location.