My recent favorite comedy movie is The Hangover I. This movie is so entertaining, I laugh from start to end.
Apparently the story of a bachelor party goes wrong is good for a sequel. The Hangover sequel counts three now. My favorite is still the first one.
Other comedy movies I love are Snatch, Sister Act, A fish called Wanda, Home Alone, Mrs. Doubtfire, Think like a man, Beverly Hills Cop, Coming to America, When Harry met Sally, Fighting Temptations, Four Weddings and a funeral, The Black Adder, Y tu mama tambien, Mr Bean on holiday and many many more.
Some of these have an absurd comedy, some offers slapstick and some require the audience to think before bursting in laughing.
Either way, comedy is entertaining and mood uplifting.