Dump 15–25 bottle caps in one bowl on a tray. Put two or three empty bowls next to it. Place tongs on the tray.
Pick up one cap with the tongs. Move it to one of the empty bowls. Don't say which one.
Sorting by color. Sorting by size. Then re-sorting differently. Then mixing them all back together and starting again.
Set up a "delivery route" — caps must go bowl 1 → bowl 2 → bowl 3 before they're done. Hide a small "passenger" inside one cap. Race the clock.