If your audience look as excited as those below then WORRY!
I may be doing some talks on IPSec, VPN quarantine, VS05 new features, secure code and the 'open source revolution' at my school (dependant on a variety of factors however am preparing them for the experience should they go ahead or not). Hope people don't look like that!
Ha! I had something like that when I was doing a lecture in a movie theatre. Luckily my laptop's audio was plugged into the 24 speaker system. Window's "ding" is nerve shattering coming from all directions!