Transit radar produces an on demand transit map showing all the stations that you could reach from a departure station within a limited time frame and the optimum routes to reach them.
The resulting map is plotted as a flattened time cone - ie. radially, with the radius representing the total time from the start point to reach each station, and so proximity is distorted by the quality of transit links. Currently it covers all public transport modes in Berlin and some of Brandenburg.
Please let me know if you think this would be useful for anything or even just let me know what you looked at. Styling and layout tips also greatly appreciated: firstname.lastname@example.org.