GOG is offering two classic PC titles for free. EA and GOG have made both Worlds of Ultima: The Savage Empire and Ultima: Worlds of Adventure 2: Martian Dreams available for a net total of zero dollars, so you can try them out if you missed them back in the early 90s.

The free releases came alongside GOG's announcement of its summer sale. This year's theme is "Battle of the Games," in which games are matched head-to-head for user votes. The winner will get a 60% discount, and the loser will get a 40% discount. Today's match-up is Myst: Masterpiece Edition vs The 7th Guest, with Myst taking a slight lead so far.