Expat get-together planned in Bangkok?

I really have no idea, and don't get out to expat events all that much, but I can save you some clicking around and mention a couple of places that might be better to check.  Internations is a different kind of expat group that holds lots of meet-up type events.  The downside is that they feel a bit like work, and it's probably not a hurdle for most but they charge to attend those, 300 baht or so, maybe $10, and they usually offer a drink to offset that.  There is a really informal meet-up group on Facebook, Bangkok Hangouts, but they don't post many meet-ups.  Any number of expat groups or sites would be options; those two just stand out since I've attended events through them.

Impact is getting pretty far out of town center; no matter what turns up you'd likely need to commute to attend something, unless it somehow tied to people attending an event there, but that might not turn up online.  That end of the BTS line (skytrain) stops at Mo Chit, not all that far from there, and that line runs along Sukhumvit, the center of lots of different things in Bangkok, so it might not be so bad to get in and back out of the middle of town.  Of course there really is no one downtown center in Bangkok but socially related to expat events a number of stops along that street / train is more or less it.