remake of the other topic without cursing in the title. for me it's those horrible frat boy games. and moral combat slap fight. so many of the games that addictinggames makes are bad.
As far as commercial games are concerned, I'd have to say that the worst one ever is Indiana Jones and the Infernal Machine, for the N64.
Indie, on the other hand, offers a much more varied selection of suckiness. There's a horrible website called Firestorm Studios that releases bad games periodically, but "Frontline 2" has to be their worst ever, taking the prize for Worst Game Ever.