The Pan-Massachusetts Challenge 2010 season is off and running, er, pedaling. Heavy Hitters got the wheels turning last week when registration opened for alumni who earned Heavy Hitter status through their fundraising levels. Yesterday, registration opened for all PMC alumni. On Jan. 19 anyone can register to be part of the 31st annual event. We've been following the registration process on Twitter. Follow us here. Here are some recent Tweets. You can follow the conversation by searching here. If you Tweet about the PMC, use the tag #PMC.