A number of Squeakers usually attend the OOPSLA conference each year, including folks from original Squeak Central and the current board.
There is always a Squeak "Birds Of a Feather" (BoF) session on one evening of OOPSLA - traditionally on tuesday evening. At the BoF, a bunch of Squeak/Smalltalk folks gather together and give informal demos/presentations of things that they're doing with Squeak. We usually sign up informally to get a grip on how many presentations there will be.
The last couple of years (well, perhaps not last year though), there's also been an informal "Squeak Bug Fixing Party" at the Camp Smalltalk area of OOPSLA, in which anyone is free to participate. See http://wiki.cs.uiuc.edu/CampSmalltalk/Squeak+Bug+Fixing+Party.
