Fabric Bingo - you can either premake the boards or have kits ready for participants to sew a board up. When done, the boards can be saved another retreat or used as 10" blocks for one or more quilts.
You need 25 2 1/2" squares for each Bingo card. One should be black for the "free space" in the center. You should have 5 blue, 5 red, 4 pinks/purples, 5 yellow, and 5 green. Each fabric should meet one or more of the following themes: batiks, dots, florals, geometrics, hearts, leaf prints, metallic, holiday, novelty, paisley, plaid, solids, tone-on-tones, stars, strips, reproductions (like either 1930's or Civil War) or any other theme you can think of. Sew 2 pinks/purples on either side of the black piece to make the center column. Sew each of the other columns together so that you've got a blue, red, green, and yellow column. Then sew the columns together keeping the center column in the middle, but ordering the other 4 anyway you want.
Here's a tutorial for making the board: www.amqg.org/pdf/bingofabdir.pdf
To play: instead of calling out a letter & a number, you'll call out a color and a pattern, like "Yellow tone-on-tone". If you want, you can just call out the pattern. Participants use buttons or other small marking devices to cover the board. Regular Bingo rules apply to win - must cover a straight line or any other variation that is used in Bingo.