Yellowrock is a sandbox fantasy campaign using the Swords & Wizardry rules. S&W is a “retro-clone” of the original Dungeons & Dragons little brown books, plus Supplement I: Greyhawk. The campaign will be played online using Roll20, a virtual tabletop.
A “sandbox” campaign, at least as the term is used here, is sometimes called a “hexcrawl.” The focus of the game is on exploration and adventure. Player Characters are based in the village of Yellowrock, a small frontier village clustered around an ancient stone hillfort. When the campaign begins, the characters will have only the vaguest idea about the immediate surroundings of the village. Where they go, what they do and what they discover is up to them.
You can click on the Maps tab at the top of the page to view the current Player Map for the campaign. At the start of the campaign, most of the hexes are blank (gray). This is because the characters have no idea what is in those areas — filling in the map through exploration and discovery is one of the primary goals of the game.