My college friends and I are like that. We don't talk every day, but we have standing things; once a year steak night at Capital Grille, Thanksgiving Day at the Manchester Road Race, March Madness, the Super Bowl, etc. etc. I've known these guys since I was a freshman in college, and at this point, they've seen the best, the worst, and the weird of Stadler, so there's literally no judgement at this point. That's a really nice feeling.
The core group - five or so - we refer to as "phone call friends", meaning, if any one of us gets a phone call in the middle of the night, the answer is "name the time and place" and we go.