Well, be prepared to explain your project/results to the others attending. Go to your supervisor and ask him/her if you are expected to show some of your data (if he/she hasn't told you yet this seems unlikely, though).
But you could just as easy end up with a table full of profs reminiscing about conferences they attendet, etc.
Don't worry too much, look interesed at all times and don't order spaghetti!