Comments #7 and #30 from jstwannabnude and DallasDad respectively resonate the most with me. I like to bond with men just doing "regular" things. That's not to say that it can't be or isn't also bonding to arrange activities like swimming, hiking, etc and do them nude together. But for me there's something about being totally exposed around one another and allowing ourselves to slip into "everyday" things like just having a casual chat about anything at all, drinking a few beers, watching a game, or just watching any old crap TV, watching a film, cooking something, sitting outside smoking a cigar, etc etc that can really remove another layer of ourselves and help us to not be so conscious of being naked. And as those layers slip away, I find it becomes easier and more comfortable for two (or more) men to open up - for those casual conversations, however banal, to become more detailed, revealing, and meaningful.
I believe it also helps us to become more comfortable with our own bodies and each other's. In my experience the boundaries we normally hold with sexuality and identity and space start to flex and bend. And I don't mean to say that in a sexual context. I suppose what I mean is, I find people don't get so nervous about a touch on the arm or leg when laughing or making a serious point. People don't get so awkward about things like burping or farting or body language or posture. I know these sound like little or crass things but I believe they are important details in helping to bring two or more people closer in any form of relationship regardless of sex or sexuality or intention by way of helping us open up to each other and ourselves.
Having said all that, I believe the goal is the freedom and relationship that two or more people develop through nudity that is important so whatever activities work best for those two people to achieve that are the best ones for them.
My favorite male bonding activity is camping, a good cigar and maybe taking the ATV's out on the trails.
Those are seriously great...I love camping and hitting the trails. nothing like ending the night around the fire with a drink in one hand and a cigar in the other BSing about life and stuff.