Honestly, no joke, I don't think I played more than a few minutes of Resident Evil 4 without two of my best friends (one male and one female) and my little sister passing the controller back and forth the entire time. Despite being a completely single player game, its cinematic nature and fairly easy controls really did make it fun for everyone that was in a certain age group. Just like siblings who are 5 and 7 might play Jak and Daxter together, my 19-year-old sister and I really enjoyed RE4 together.

Just because a game doesn't necessarily appeal to all-ages doesn't mean that it can't be a party game. Guitar Hero is, to a degree, an example of this.