This is a great site for chemistry fun while you learn. They have multiple games, most free if you want to print your own.The card game that I am using is 18. It is played like 21 or blackjack but uses metal centers and ligands to get to 18. A fun way to teach 18 e- rule and familiarize students with ligands. My husband suggests using Dove squares instead of the optional benzene "chips" for "betting" which I think will make it very competitive.
Slap count also teaches counting 18 electrons.
They also have chemistry pins - both organic and inorganic and an NMR pin... my inner geek is very happy. Pins cover class topics and lab skills.
Bring the game(s) and let them play. Use chocolate as the betting chips to motivate students. Use pins as year end prizes for students who excel at skills.