How do 50-somethings find friends in Madison?

I understand this is a common post - how do you find friends in Madison? But, anyway, how do you find friends in Madison (particularly for men in their 50s)? I've been here a few years and haven't found much in the way of community (though I love living here with my family - the kids now off to college and beyond).

Things I like: sports, books, the arts, the Ice Age Trail.

I'd like to think there are other guys out there just wanting to get a beer, or watch a Mallards game, or check out some indie film every so often with some other like-minded guy.

Thanks for whatever thoughts you might have.