Real time tracking of Boston subways, buses and commuter rails.
Made mostly in a weekend and available free and open source [1]. Though it's simple, I think it gives a nice overview of the trains and buses. Boston has stop prediction so in some sense it's kind of frivolous. I think the biggest 'innovation' was to integrate the "map icons" into a nicely visualized open street map [2].
Not super popular but it's been running for around 2 years with ~20 hits per weekday.
