I have them with my bro and his girlfriend. We generally go for Wario Ware which has a super multi-player mode. Super Monkey Ball (not great game but great 4 player) and some Wii-Sports mainly bowling, Girls seem to struggle with Baseball, My Wife is pants.
(Hand to Eye co-ordination)
Will Get Mario Party 8 when it comes out in the UK.
I also have PS2 nights for Pro Evo.