Two months ago I joined a local running group through the Meetup.com social organizing website. I knew a couple of the guys in the group from the pub run that I'd been attending for a while, and they invited me to go out to the Monday night runs with this group. I'd rejected a couple of previous invitations because I was intimidated by the idea of imposing myself into an already established--and rather serious--running group. But I also had the Chicago Marathon--a race I'd signed up for a bit spontaneously--looming in October, which meant I'd have to do some heavy training throughout the summer. Based on previous experience, I knew I was not likely to tough out the hell-like heat of summer training on my own, so I thought I'd give the group running a go. I should also add the disclaimer that I had a crush on one of the guys who'd invited me to join. (If you see the potential for disaster already, you are smarter than I was.) My first meet-up with the group wa...