Do you like to have racing games because that will bring more excitement.The stuff my wife and I used to play (before my son was born):
Combat Training mode on CoD:Black Ops pretty religiously (she's not a "gamer" but handled herself well against the bots)
Bubble Bobble Neo
Bejeweled Blitz
Borderlands (she enjoyed shooting things a lot more than she thought she would...)
Gears of War 1
UFC Undisputed (she enjoyed pummeling someone unconscious a lot more than she thought she would...)