The point of activities fair is to recruit frosh. So, any frosh who come to meeting on the day of the fair should be recruited to play chess, and there should be loud shouts of ``live chess!'' and other such things immediately before the game. Activities fair tables are usually arranged in a large circle, so the chessboard should go in the middle of the circle.
One problem with chess at activities fair is that the game often goes on for too long, and the pieces get bored. Use your judgment: if people are getting bored, one of the kings should play badly to end the game. Also, it seems unfair to stack the deck against one team or the other, but i played a game one year in which one of the kings was a significantly better chess player than the other, and the game ended naturally in an appropriate amount of time, and no one seemed upset.
Also, of course, someone needs to man the table during the chess game. The table should be stocked with things representative of swillish activities -- board games, books, and old copies of BEM work well, Decorative weaponry doesn't hurt -- and should have a large sign on the front (there's currently one in George, but it may disintegrate sometime) with our name and the time and location of SWIL meetings. There should be a couple of people at the table at any time, and they should have sign-up notepads for the SWIL mailing list, and for the trip to Ren Faire. The signup notepads should ask for people's name, e-mail address, and class year, so it's easier to put them in the right place on the SWIL list. If there are leftover BEMs (there are always leftover BEMs), you can put out a stack and let people take them.