Attend #SIC2011 this week. Were you as un/impressed as I?
Despite this being the "Seattle INTERACTIVE Conference" (emphasis mine), the interaction model followed the traditional television model: programmed spaces were dimly lit, passive, and so large that looking at the big projection screen (instead of the speaker) was the only option from many seats.
This is experience is common to many conferences I've found. Here's the LP take on how to fix it...
10 Ways to design Professional Conferences like Adult learning experiences