You.

"John!" Sarah smiles, pointing at you. "Join us in removing your shirt, please."
You oblige pulling your shirt overhead and adding it to the pile. You've been a little sedentary lately, and you're a little self conscious about your physique. You have some muscle definition in your arms and shoulders, but no six pack, and more body fat that you'd like. Sarah gives an approving nod when you finish, but Miranda doesn't give you anything to go on but a brief look. If I'd known we were going to be playing dares, I would have worked out more.

The dares continue around for a few minutes, until all the players are topless, with Tom daring Miranda to take hers of with a little dance and twirl in the middle of the room. You were rapt at attention during this particular display. As you look around the room, you can see the range of physiques on display. Your own pale, slim, somewhat fit physique, Matt's lean and toned build, the body of a runner and soccer player, and Tom's gym rat chest and arms, complete with douchey tribal tattoos on both arms. You tell yourself to relax: Miranda isn't the kind of girl to be hung up on appearances alone... right? She always shoots Tom down whenever he tries to his slimy pick up artist bullshit.
The girls also run the gamut from modest but perky Nicole, still occasionally fidgeting in discomfort. She doesn't even wear bikinis usually, though you note with some interest that her stomach is flat and her waist is small, accentuating her modest rack. Miranda has her 36C bust in a sexy bra that accents her cleavage in a way you can't stop admiring. And then of course there's the busty Sarah in her blue silky bra and curves.
"Alright...now that we're all shirtless, let's have some real dares." Sarah pokes at Miranda in the love handle, making her jump and squeak. "Pick a name, Miranda."