Shorty, does everything outdoors have to be a cardio workout? What's wrong with a nice game of softball, taking it easy? Go for your 5 mile run some other time.
I moved here in 1997, got divorced in '99, and within just a few years, I'd made scads of friends here in Madison. And I'm one of the quietest and most introverted people you'd ever meet (as a fellow teacher described me).
I missed the Friday Night Skate in SF, so I started Mad City Rollers and for quite a few years, we had a Friday Night skate right here. I gave free inline skate lessons to hundreds of people outside of Willy St Bikes (now Machinery Row). I went to the UW Ballroom Dance Association dances and resumed the dancing that I had given up when I got married, and took lots more lessons. I helped start a swing dance club (Lindy Messengers) and gave lots of swing dance lessons at various places. I started Madison Freecycle, which put me in touch with that many more fellow Madisonians.
In 2002 or 2003 I started running with the Hash House Harriers running/drinking club. So you're not a beer drinker, big deal. Neither are some of my fellow hashers. Some drink wine, some just drink water.
I've gone to a great many Wednesday night bike rides, and met some great people there too. Although I'll admit that bicyclists tend to be the most exclusive group I've ever met, so I won't necessarily recommend that.
These aren't to brag about things I've done, they're to point out that a complete introvert/geek like me can get out there and make the effort and meet people, and get a good workout in at the same time. I recall being out with a friend on State Street in around 2003, and I kept running into people I knew, again and again--it felt like a small town to me at that point.
Turn off the computer and go out and do something!