We've played fabric bingo. You can either have the squares pre-made and ready to go, have them kitted up so participants can sew them, or send directions out for participants to make and bring the boards. The boards could then be used as blocks in charity quilts.
I've also played left-right-center. You need special pair of dice (they say L, R, C on them instead of the #'s 1 - 6). Everyone starts out with 3 fat quarters. Roll the dice and do what they tell you: L = give one to the person on your left. R = give one to the person on the right. C = put one in the pot in the middle. Last person with any FQ wins the pot. This would be more a small group game (I think we had 9 - 12 ladies in the group).
We also do a FQ swap. We've done it different ways
- have one sitting at each plate setting at a meal (and then the leader made us rotate seats :-))
- call names a few at a time to pick from the FQ's
- give them away in packs to a few lucky people.
We've done block raffles as well. Assign a block or theme for everyone to make. (like green pinwheels or any 1930's 12" block) You get 1 chance for each block you make. If there's more than enough for 1 quilt, divide the blocks into 2 or more sets. Raffle off each set.
Free table - if you've got patterns, scraps, magazines, etc. you no longer need, deposit them there. Others are free to take as much or as little as they want from it.
Don't forget the snack table. Ask everyone to bring their favorite snack (if homemade, bring some copies of the recipe!) You might want to have a large sealable container (like Rubbermaid storage boxes) to put the goodies in overnight - we have to at the camp I go to, b/c otherwise we might get mice :-(.
Always have some sort of show 'n' tell.
Make sure each participant has a name tag (or ask them to bring one).
Rather than let each person have their own iron, set up ironing stations throughout the sewing area. Irons use a LOT of power and too many can zap the system.
Make sure that if any electrical cords have to be where people walk (like an extension cord on the floor) that they are taped down to prevent tripping.