What co-op multiplayer (single PC) game?

I've enjoyed playing Marvels Ultimate Alliance with my son and wife all three of us on a PC cooperating through the villains, having a great family time.

It's over thought, and I am after another game with similar playing style.

A game that supports up to 3 players using gamepads, cooperating through the levels without a lot of violence and involving action.

Any suggestions will be greatly appreciated. Many thanks

Trine is a good one, you can buy it from Steam as well as retail. it is a ' physics-based action game where three characters allow clever solutions to challenges created by hazardous puzzles and threatening enemies.'

Burnout Paradise has a nice "Party Mode". It's only one at a time in a pass-the-controller type vein, but it's fun.

Also, second Worms - Worms 4 Mayhem's my family's favourite for multiplayer.