Heh, one club I walked into with my board and I was sternly told "put that back in your car unless you want to lose it, we provide the sets here" lol 
But really, clubs love to have new members. If the social aspect wasn't important to them, they'd all be at home on their computers.
Social expectations? Well if you walk up to the table/sit down and start watching a game, they'll know you're a player and someone will likely offer you a game. Or once the game finishes they'll likely rotate out (again, if they wanted to play the same guy 100 times, they woudln't have come to the club).
Part of the fun, for me at least, is discovering the pecking order... and in my experiance most players want to know how they stack up against the new guy as much as the new guy wants to know how he fits in (even if he suspects he's pretty weak). So it would be impossible IMO to watch games the whole night silently and have no one offer you a game or start a conversation.
After a game, some players like to analyse. If you lost, and you think you had a winning move, it's better to say something like "I was considering this move, what would you have done?" instead of "my move was stupid, if I would have played ____ instead you were toast" And of course a sure way to get them talking is to ask for general pointers or "where did I go wrong"
It's not necessary to do a rematch, but in my experience players who are close in skill will often switch colors and play again. Usually this happens with "play again?" -- "sure" or "again" -- "no thanks" and the like. If you play again, you'll switch colors regardless of who won.
Oh, and players don't announce check or checkmate. Some new people don't realize that. As a courtesy you assume your opponent is good enough to know that a move puts them in check or checkmate.
If you're behind a ton of pieces, it's polite to resign. Only resign if you think you could beat someone much better in the same position with colors reversed. Don't resign because you think it's expected. Most players respect this. I usually resign by laying my king on it's side and saying "OK" or just "I resign" You really can't mess up resigning though :p
Hello,
I don't post to message boards very often, so I apologize in advance for any e-social faux pas.
I am wanting to become more active in a local chess community, and so I have a question for the club players out there. If I go to a local club, what will be expected of me? I will bring my own supplies, for sure, but should I sit down with anyone with an open board? Should I set up a board myself? I expect I will be weaker than most of the players.
Basically, I like to know what the social expectations are in a new social situation, so, if you're willing, will you shed some light on being a new club player? Thanks! -tkg