We've been trying to do the "family games" thing a little bit. Not in any organized kind of way, but more in a can-I-manage-a-game-instead-of-sending-them-down-to-watch-a-Saddle-Club situational sort of approach. And occasionally one of us will actually pull it off (where "pull it off" = distract the girls from watching a video until it's too late to start).
Lately two of our favorites have been:
crazy aches - which has something to do with 8s and everything to do with being crazy. We generally turn all the cards upside down and flip them over one by one until someone gets a match.
gold fish go - deal out 6 cards to each player who lays them face up in front of themselves. Spread the rest of the cards face-down in a pool between the players. Player 1 asks another player if they have a match to one of their (player 1's) cards. Note: that player 1 can see the other cards, and any suggestion that we try it with cards hidden results in loud complaints about it being too hard that way. If, by some miracle, the asked player does not have a matching card, they say "gold fish go" and player 1 draws a card from the pool.