I've written about this before, but it's been quite a while. In 1988, a movie came out with the tag line "The outrageous comedy about the world's greatest detective and his bumbling partner... Sherlock Holmes." The movie was called Without a Clue, and this movie is quite possibly the most underappreciated comedy I've ever seen. The timing of the two leads is impeccable - Ben Kingsley was absolutely perfect as Dr. John Watson. The plot itself, while not necessarily the most difficult mystery, was certainly full enough to support the film. And the writing was absolutely spot-on.
Michael Caine does great with some physical comedy, but his delivery is part of what makes this film so special.
Jeffrey Jones (of Beetlejuice and Ferris Bueller fame) complements the leads with a terrific performance as inspector Lestrade.
If you are in the mood for a movie with a plot and actual dialog, this is the one you want. While there is some action, this is not an overpuffed special effect with some words thrown in to sell it as a movie. This is the real deal, and a comedy that is rare to come by these days.