Source: http://gizmodo.com/5537409/real-gaming-for-macs-is-finally-here-with-steam
Steam for Mac is officially available, along with a sizeable trove of games—including Portal, which is now free for everybody.
Valve's plan is to release a new set of games for Mac every Wednesday for the next few weeks. This week, notably, every game has SteamPlay, which means you buy it once, and it'll run on all Steam-supported platforms (which implies that not every Steam game available on Mac and PC will necessarily be SteamPlay style). I know, games have existed on the Mac for a long time. But the promise of true multiplatform computer gaming on the largest scale in a long time is pretty thrilling. (As someone who does most of their FPSing on a desktop PC and owns a Mac laptop.)
I honestly can't tell you how hard it is not to pee my pants right now (and I just went to the bathroom).
Right now, there 63 games/gamepacks listed as being available for Mac—Torchlight, Civilization, the LucasArts action pack, among others—though no TF2 in sight, for now. (Though I'm still chaffing that it shoves your game files inside of the Documents folder.) As noted, Portal's only free until May 24, so get in there. Here's the full list on Steam's site:
TriJinx: A Kristine Kross Mystery
World of Goo
Zuma Deluxe
Sid Meier's Civilization IV
And Yet It Moves
Braid
Escape Rosecliff Island
Civilization IV: Warlords
Civilization IV: Beyond the Sword
Sid Meier's Civilization: Colonization
Sid Meier's Civilization: The Complete Edition
BRAINPIPE: A Plunge to Unhumanity
Diaper Dash®
Machinarium
Football Manager 2010
Bob Came in Pieces
KrissX
Sam & Max: The Devil's Playhouse
Galcon Fusion
Quantz
Torchlight
Toki Tori
Valerie Porter and the Scarlet Scandal
Parking Dash
The Nightshift Code
Nightshift Legacy: The Jaguar's Eye
Mahjong Roadshow
Hotel Dash Suite Success
DinerTown Detective Agency
Fitness Dash
Gemini Lost
Atlantis Sky Patrol
Fairway Solitaire
Professor Fizzwizzle and the Molten Mystery
Unwell Mel
My Tribe
Tales of Monkey Island Complete Pack
Osmos
Wandering Willows
Wedding Dash 2: Rings Around the World
Zenerchi
Dream Chronicles: The Chosen Child
Diner Dash: Hometown Hero
Cooking Dash
Chocolatier: Decadence by Design
LUXOR: Mah Jong
The Dig
LOOM
Indiana Jones and the Last Crusade
Indiana Jones and the Fate of Atlantis
City of Heroes: Architect Edition
Peggle Nights
Luxor
Luxor 3
Portal
Peggle Deluxe
Bejeweled 2 Deluxe
Bookworm Deluxe
Chuzzle Deluxe
[Steam]