My older students love to experiment with bigger numbers. When 3 students play, one likes to use a white board to write down whatever math problem they are working on while the other two count out the beads. The children put the first set of counting items in the first cup, and the other child puts the second set in the second cup. They all fall through to the basket, and then they count them all up.
Cool party idea. You hire the artists to bring supplies and teach all the kids to paint the same picture. They clean up! (You provide the "cookies" part.) Cookies & Canvas out of Indianapolis and Bloomington, IN or Oklahoma City. Adult version: Wine & Canvas.