The fan project Black Mesa (previously known as Black Mesa: Source) fell silent a long time ago, but has shown public signs of life. A new album on their official Facebook page includes confirmation that a first release is inbound, along with a handful of new screenshots showing development. This follows the team's June 9th posting that stated if their page for 20,000 likes (which was reached) that they would post "some exciting new media".
For those of you not aware, Black Mesa is a fan attempt to recreate the first Half-Life game in a modern engine. While Valve officially made Half-Life: Source previously, it was simply a port of the old media to the new engine. Black Mesa is a recreation, working from scratch with custom media.