Apparently, there's this thing going around lately called Halo 3 day. It's where we all get together (not in a party) and log on Matchmaking. Mainly Social Big Team and custom games. We stay in game chat, talk to each other, and party up. Stuff like that.
It looks like it is so far going to be on September 25th.
This looks like the main thread: http://www.bungie.net/Forums/posts.aspx?postID=64309342&v iewreplies
Can't wait!