Games where users can create own content and share it with other players

[happylakers]

Hello,

I search games where users can create their own content and share it with other players worldwide.
For example Labyrinth 2 i don`t know if this is the right name. In germany its called "Labyrinth 2".

Are there some good games, where i can download new maps, cars, missions etc...

Thank you for your help!

happylakers