A game near and dear to my heart: Llano Estacado. Created this when I was in grad school to pass the time and goof around. Now bringing it to the public. 

https://free-radicals-press.itch.io/llano-estacado-a-rummy-hack

The game is a rummy-style hack, complete with runs, books/sets, and tricks. Easy to start, addictive as hell, and best with large groups.