Though not immediately available, this morning's announcement claims that GOG will enter the Linux market at some point this Fall. "We're initially going to be launching our Linux support on GOG.com with the full GOG.com treatment for Ubuntu and Mint," the announcement stated. "That means that right now, we're hammering away at testing games on a variety of configurations, training up our teams on Linux-speak, and generally getting geared up for a big kick-off in the fall with at least 100 Linux games ready for you to play."
Among those 100 are games already available to Linux, but the announcement claims that GOG.com will also play host to "a variety of classics that are, for the first time, officially supported and maintained by a storefront like ours."
Unfortunately, the announcement offers no specifics on exactly which games we might see available on Linux. Not out of malice or subterfuge, but because the team working on Linux support hasn't yet nailed down which games it will be working on. Presumably we'll hear more about the full slate of games on offer as we move closer to the program's launch this Fall.