The best thing about those is the odometer...there should be a decent celebration for every major milestone (1k, 5k, 10k, etc).
Finally broke down and bought a bike computer (wireless Cateye, total bad ass little tool). We managed to bike 15 miles today (over to the stadium, around the Yards Park, and back to Crystal City) in about 90 minutes (10 mph pace). Call Rizzo - we're ready for the home opener!