re: Most ridiculous comedy premises

This is actually the opposite of what was asked in the OP, but if you really think about it the plot to dumb and dumber would make for one hell of a drama.

-rich woman's husband is in deep and drops off a briefcase full of cash at the airport for the bad guys
-good hearted innocent civilian sees this and retrieves it instead
-down on his luck, he decides to return it to said woman
-the bad guys are on him, but he doens't realize what's going on. Cat and mouse chase across america ensues including several meetings between parties
-good guys end up meeting friendly stranger
-good guys arrive at destination with cash. Bad guys get the drop on them and things look bad.
-friendly stranger shows up, who is actually working for the feds and has been following both parties the whole time
-woman gets her husband back from the bad guys, who get caught


With teh right cast and script writing a movie like that could do work in theaters.