We may already have a winner for the best, smartest booth swag at Greenbuild '07: the "rethink the dress code—CLO.08" t-shirt from Big Ass Fans. Technically, these shirts may not be booth swag, since they 'cost' the very special Greenbuild price of a one-dollar donation—which funds are met in kind by the Big Assers and used to support ASHRAE Research on Standard 55: Thermal Environmental Conditions for Human Occupancy. CLO.08? It's the thermal insulation value of a t-shirt as defined by ASHRAE. Still don't get it? Yeah, I wasn't a big enough geek to figure it out either... but now I'm in the club, and you can be too. I'm going to quote straight from their website for the explanation, because I couldn't possibly say it any better than they have:

LOSE THE TIE. TOSS THE JACKET. DROP THE TROUSERS. Okay, keep your pants on. But do take it all off right down to your clo.08 (the clothing thermal comfort value of a t-shirt). Big Ass Fans knows that dressing appropriately for your environment means less energy is needed to keep people comfortable. Fewer clothes; bigger energy savings. We like the sound of that. NEED PROOF? Ever heard of a little island nation called Japan? In the land of the rising sun the government mandates thermostats in all public buildings to be set at 82 degrees Fahrenheit during the summer months. The working men and women are urged to abandon their traditional business suits and don skimpier attire to stay comfortable. The result of this clothing optional approach has been a 1.14 million ton reduction in carbon dioxide emissions. WHAT ARE WE DOING ABOUT IT? To show our commitment to the cause of under-dressing, we are contributing 100% of the donations from our clo.08 t-shirts to ASHRAE Research on Standard 55 - Thermal Environmental Conditions for Human Occupancy. Go ahead, save money and look charitable. You know you want to.

I also got Josh Eddy, their Engineering Sales Manager, to spell it out for me on tape (1.7MB mp3 file). You can order these gems at the normal $5 rate from their website. Still really cheap! And if you can make it to Chicago in the next couple days, the little plastic donkeys are free.