If you are developing applications in the social media / social networking / web 2.0 space, you should know about Social Dev Camp East, coming up on May 10, 2008, in Baltimore. Some info is in PBWiki, although most of the activity is happening on the Facebook event page. It looks like some great topics and events and given that Dave Troy is one of the organizers, I expect it should be good. Dave's the guy behind Twittervision and several other sites and is also the one who put the open source Asterisk PBX running on top of a Roomba robotic vacuum cleaner (seriously... "Press 1 to start sucking"!).
On the wiki there are already a bunch of folks signed up and I look forward to hearing about what happens. (I won't be able to attend due to other commitments.)