It's a shame that most people only know of Alec Guinness as Obi Wan Kenobi. He looked the part and delivered his lines with gravity ("I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were suddenly silenced"). But he could have played Obi Wan in his sleep; it wasn't his most interesting or entertaining role.
Guinness was a fine dramatic actor, and he also did wonderfully well in comedy. The following are two movies showcasing his comedic talents, both movies made by Ealing Studios after WWII.