Worst performance - vote now!

[Neville]

James Belushi in everything he has ever appeared, except (maybe) that ER episode.

And I think Dolph Lundgren was also to blame for the lame acting in "Rocky IV". Remember those close-ups where he tries to look threatening? I am still laughing...
Not to mention Carl Weathers... That scene where he and Rocky are talking in his room before the fight with Lundgren, when suddenly Rocky starts saying that Apollo is fighting himself is a classic of bad acting + bad dialogue.

[onionhead]

Ben Johnson in anything--an Oscar for  The Last Picture Show???  How the hell did that happen?

[trala-log]

george clooney- batman and robin

cuba gooding jr. -that guy sucks sack no matter what he's doing

[Feathertop]

I'd have to go for Richard Burton in THE ASSASSINATION OF TROTSKY and Paul McCartney AS HIMSELF in GIVE MY REGARDS TO BROAD STREET.  When you can't even portray YOURSELF convincingly your performance may be so far BEYOND bad that perhaps the whole AWARD should just be named after you while the also-rans compete to win the trophy.