Assuming it's not something from the recent flood of Steam Greenlight trash, I think it must be something from the early to mid-nineties. It's very hard for games to gain notoriety for their terribleness, and to be worse than Superman 64? It would have to be something catastrophically terrible, but with a lot of hype behind it.

Seeing as we can rule out E.T, I can't even fathom a guess!