I tend to spend a lot of time in the Expo Hall at Greenbuild. On the Greenbuild 2009 website, the Greenbuild International Expo page says:

This year's expo hall in Phoenix boasts over 1,800 exhibit booths showcasing the latest in innovative products and services.

Were you there last year? That was 800 booths. Double that, and add some. At this writing, there are 1,057 exhibitors listed for this year; but let's assume that there will be at least the promised 1,800 by show time. Here's the expo hall schedule:

Tuesday	5:30pm - 8:00pm
Wednesday	9:00am - 5:30pm
Thursday	9:00am - 5:30pm

The Expo is open a total of 19.5 hours — which is 1,170 minutes... or 70,200 seconds. Divide those seconds by 1,800 booths. You have 39 seconds to linger at each one. If you visit only half the booths, the time goes up to 1:18 each. Check out the video on the main Expo page, though — our own Nadav Malin in a Fortune Magazine video shot during last year's Greenbuild Expo (as previously noted here on our blog).