To your OPLove/FeedBlast idea… you might want to take a look at this (academic) review of the “cocktail party effect”, which is closely related to what you’re considering implementing:
http://xenia.media.mit.edu/~barons/html/cocktail.html

Also, consider getting in touch with Bruce Walker at GT; he specializes in sonification and might be able to put you in touch with some folks.
http://sonify.psych.gatech.edu

About the Dirt Party, I had a similar idea to pre-register your IM address and have a chatroom before the meeting so that people could get introduced and have something to talk about at the party. Even some nerdy friends thought that this was way too nerdy to even consider, but I still think it’s a good idea to have the ice a bit pre-broken.