Aha. I didn't until recently, but my PCP yelled at me to work some exercise into my routine; given my current phyisque that pretty much limited me to walking.

After a week or so I found I was walking down different streets everyday, so I grabbed a map and it morphed into Le Grand Prix du Somerville. I've got everything west of Cedar Street covered already, plus north of Highland over to Lowell. It's been a great way to get a better sense of the city. The only moderate hassle has been walking down dead-end streets, and getting quizzed on my efforts.