I can't help thinking that a group for single gays is, no matter what, always going to be about the hookups. It seems like group activities would be more fun if done for the sake of the activity, not for dating purposes. That is, not specifically a LGBT group.
(Anyway, you'd be surprised at the guys who made passes at me when I was in a "straight" scuba club. Something about compressed air and mild hypothermia brings out the beast in young guys, I guess.)
Other than that, yeah there are the gay sports leagues, the gay choral groups, gay hiking groups, etc. I see these advertised on bulletin boards in gay bars. Even gay ballroom dancing lessons seemed mildly interesting, but too far for me to drive.
Hmm... I see on their web site that the gay hiking group is coming out to my neck of the woods next month. Maybe I'll give them a shot.