Rummikub
Rummikub is loosely based on the card game Rummy but instead of cards we use tiles. The object of the game is to play 3 of a kind or runs of three plus in the same colour. You start with 14 numbered tiles and every time you can not put down you have to pick up another tile. The winner of the game is the person who manages to put all their tiles down first.
We play it for FUN but it is very good at keeping the brain challenged and can become addictive.