i would also have to go with the 67 casino royale, it is hilariously bad! and the actors were just having TOO much fun being as campy as possible, i loved it!
Here are some of the credited actors who appeared in the film.
A: Woody Allen -- Ursula Andress
B: Gregory Bayldon -- Jean-Paul Belmondo -- Jacqueline Bisset -- Barbara Bouchet -- Charles Boyer
C: Ronnie Corbett -- Bernard Cribbins
H: William Holden -- John Huston
K: Kurt Kaszner -- Deborah Kerr
L: Daliah Lavi
N: David Niven
P: Joanna Pettet
Q: Anna Quayle
R: George Raft
S: Peter Sellers
W: and Orson Welles
And, as in the case of How the West Was Won, you can make a pretty good film out of those actors who appeared in the film, without being credited. For this film some of them include . . .
Geraldine Chaplin -- Valentine Dyall -- Ian Hendry -- Angelica Huston -- Burt Kuwok -- John Le Mesurier -- Stirling Moss -- Caroline Munro -- Peter O'Toole -- and Mona Washbourne.