So, this is happening:
http://www.macrumors.com/2012/04/13/...me-firm-valve/

AppleInsider reports that Apple CEO Tim Cook paid a visit today to the the headquarters of Valve, the video game firm behind the Steam digital distribution platform and a number of popular PC and Mac games. While the purpose of Cook's visit is unknown, his presence at the company's headquarters in Bellevue, Washington suggests that it may have been of some importance potentially relating to collaboration between the two companies.

Just over two years ago, Valve made a splash by leaking a set of teaser images to MacRumors and other Apple and gaming sites revealing that it would be bringing its Steam game distribution platform and a number of its own titles to the Mac platform. Steam for Mac launched in May 2010 with over 60 titles, and Valve now offers over a dozen of its own games for Mac through the store.

Earlier this year, Valve released a Steam companion app for iOS, allowing users to browse the Steam marketplace and even purchase games for later download and play on a PC or Mac.

It is unclear just what Apple and Valve might come up with in terms of an expanded collaboration if one is in the works, including whether it would extend in some form to iOS or remain limited to gaming on the Mac platform. Valve has been rumored to be working on its own hardware offerings related to Steam services, and the company has just posted job openings related to hardware engineering for such projects.
Either a Source port on iOS or AppleTV is my guess.