How about laminating a "race course" in the inside of the lid and use small painted rare earth magnets as "cars". Or have a race course one side and a checker/chess board on the other of the laminate. Also, you may be able to draw out a cribbage "board". Use the computer to draw one up.

My $.02
"Its not a matter of being ready as it is being prepared" -- B. E. J. Taylor