In the 4.3 code, there are references to "ATVThunder" and "ATVGames," each of which point to scheduling of games, leaderboards sortable by date, the streaming of live/archived games, and a new storefront (likely similar to iTunes).
Because the Apple TV only has 8GB of internal memory, streaming seems the only way to play games via the set-top.
Furthermore, there are references to streaming like "Sedona" and "Flagstaff." Sedona is Apple's video rental mechanism, explains TUAW, who speculates the rentals will turn to streaming, for movies/TV/games.
Finally, the code references FEATURE_REMOTE_SCREENSAVER, which could speculatively lead to interactive screensavers.
Written by: Andre Yoskowitz @ 11 Feb 2011 13:31