We had great success with Cranium Cariboo as a first game. It's simple, involves just A,B,C; 1,2,3; and red, yellow, green. It teaches the concept of taking turns, and yet it is primarily a cooperative game. Balls are hidden behind doors on the board that are identified by a letter, color and number. Each player draws a single card with a letter, color or number on his or turn and can open a door that corresponds to that. If there is a ball, you put it in the collection area, and when you get all six balls, the "treasure chest" opens (just pressure trigger from all of the balls being in place.) Our son *loved* it and asked for the ball game all the time.
We're huge gamers and were so eager for our kids to play, but it does take time. Be patient. Our oldest is six, and now we're up to including him in games that we played before his arrival, so it will come. :)