Looking for "relaxing" games, info inside!

This is a hard one to describe in Topic name so... I'm looking for something I would play to relax, something that would get me in action as soon as possible and I could turn off any time, without having to wait for a savepoint or something. I don't really care about the genre. Things that I consider a relaxing category are for example:

CoD(4): MP, specifically Free For All mode. I can turn the game on virtually any time, whether I need to leave in 15 minutes or in an hour, I'm pretty much thrown into action and I can switch it off anytime without any major consequences.
Burnout Paradise. Similar to the above one, I can play it anytime, when I feel like it I can do races and stuff, when I don't I just ride around the city randomly having fun.
Terraria. It has anytime save feature, I have a wide range of options there whether I want to play "seriously" or just relax and mess around the world.

(Skyrim would count as well but I've already finished that.)

All I can think of, or rather, all I've been playing recently. Any recommendations from you guys?

Basically what I want is a game that wouldn't limit me by stuff such as having to play till the mission ends, or till the match ends etc...

guildwars is pretty solid. granted it has loading screens but on a modern machine they last only seconds. the game ahs alot to do and no 15 minute session feels like a total waste. pvp is also very fun and pretty well balanced. jsut umm dont pvp with with a paragon primary.. thats a mistake waiting to happen.