It was a cancelled ROM hack of The Legend of Zelda Ocarina of Time/The Legend of Zelda Majora's Mask which promised to add a new story, new dungeons, new enemies and bosses and new items, and to recreate the cancelled URA Zelda game for the Nintendo 64DD.
It then kind of... well, it went all over the place. It started on Ocarina of Time as a beta recreation, moved to Majora's Mask as an original game, and then everyone had a big falling out and the game got screwed over as a result:
http://www.zeldainformer.com/news/ura-zelda-recreation-project-is-completely-canceled#.VXJRDUa4itp
So yeah, does anyone here remember it?