As part of their 40th Anniversary celebration, Atari is giving away their Greatest Hits collection (iOS) for free, today only. That’s 100 classics (and quite a few not-so-classics), normally $9.99 as an in-app purchase.
Download the app from the iTunes store, then launch the app and download the games.
The catch is, once you delete the app from your device, the games are gone as well, unlike normal in-app purchases.
There’s also an Android version of the app, but I can’t tell if the free games are available on that platform or not.
Atari is also giving some swag away via a Facebook sweepstakes.