For a great introduction on Leipziger Gose search Shut up about Barclay Perkins (the best known blog on beer history) for "Gose".
There are two breweries in and around Leipzig claiming to brew Gose:
Original Ritterguts Gose (a recipe and brand which is actually made in changing breweries in Saxony) and Bayerischer Bahnhof (a Brewpub)
as well as a "Gosenschänke" a somehow traditional Gose-Pub Gosenschenke "Ohne Bedenken".
All three are remakes. Between 1966 and the 1980s there was no Gose brewed, the old breweries are shut down. Since then production was incontinuous.
more must-reads coming soon.