Any fun and good open ended, sandbox games?

mass effect and bioshock

if you have a computer, i have the best free ones ever.

www.kongregate.com - free flash game site, fun as something awesome, sign up, pretend you're kinda not wasting your time by getting points for playing these past time games
www.warstorm.com (-_-, geeky, i know, but addicting to me at least, also you may find trouble trying to be a free player, but you can get by being free, i am)

and any Roller Coaster Tycoon (not free)

i really liked Thrillville off the rails for 360
(POKEMON!!! (i'm DEFINATELY a geek, there's nooooooooo way i'm ever getting rid of that label, lol, not that i mind)) I'm getting plat. when i get the chance, for a nice twist, before i start, i'm going to my friends and using his AR to replace my starter with one of the legendary dogs of the same element (prolly water considering i already chose chimchar and the grass one, so piplup/suicune lvl 2 it is... )

Wii... anything that's a sequel to previous nintendo systems... (Super Smash Bros., Mario Parties, Mario Kart, Mario anything, they're all uber epic awesome)

other than that, i'm blanking, i am getting into the new Banjo Kazooie (originally a game and sequel for the N64, now a new sequel only for the 360, Nuts and Bolts, nothing like the originals yet fun, it is a LONG game, and so is mass effect which i think someone else already mentioned, (for a LONG game, go Mass Effect or Banjo Kazooie Nuts and Bolts))

now i'm blanking... all of these are fun though...

try to play it with you and yourself ha ha

inFAMOUS is coming out june 9th i think sometime in june its amazing

Phantasy Universe
Assassin's Creed
Mass Effect
Just Cause
Saints Row 1 and 2

halo (()()()(*** 3 ***()()(() not just halo