The developers behind the dungeon crawling role playing game, Legend of Grimrock, have just announced on their blog[www.grimrock.net], a beta of their new Dungeon Editor and modding capabilities for the game. This editor and toolkit comes along with Workshop integration to make it easy for finding new player-created content and adding it to your game.
To participate in the beta you'll need to have a copy of the game on Steam. Just right-click on Legend of Grimrock in your Library of games in Steam and select Properties. In the Betas tab opt into the beta using the dropdown there. The Steam Client should then automatically download the beta. Then you can go to Legend of Grimrock in the Workshop to find custom dungeons to download.