Hi...how many are going to the retreat?
For our retreats we are told to bring a fat quarter, a star block (or whatever block the coordinator decides on, including colors or fabrics, like batiks, jewel tones, brights etc) and some fabric squares...again size determined ahead of time..
Depending on how many are at the retreat, a certain number of the fat quarters are used a prizes for games and the remainder are used in a drawing and the winner gets all the fat quarters.
The blocks are also used as a prize...but depending on the number of people in the retreat, they are divided up into 12 or 20 or whatever and again used in a drawing. The same with the fabric squares.
All names are in one 'hat' and once drawn they are discarded so that no one person wins more than one 'prize'
I know you can do a search online for quilt games, quilting games, quilt retreat games or whatever and find lots of sites with lots of ideas.
warm quilt hugs, sue