It has become a tradition in my house to watch ARSENIC AND OLD LACE every Halloween. The tale of the two Miss Brewsters who poison lonely old men as a charity act is so familiar that I don't need to summarize it again. The movie is a typical fast, funny 1940's comedy (it is based on the play by Joseph Kesselring, which I've also had the pleasure of seeing). Though some claim that Cary Grant overacts in this movie, I think that his over-the-top comedic style is ideally suited to this "screwball" farce. The rest of the cast, including Raymond Massey as an escaped convict in disguise ("He said I looked like Boris Karloff"), Peter Lorre as his cowardly little assistant, and especially Jack Carson as the hilariously clueless Officer O'Hara, is perfect. Oh, and I almost forgot to mention John Alexander as "Teddy" (he really DOES look like Teddy Roosevelt).
There is also a welcome appearance by the inimitable Edward Everett Horton as Mr. Witherspoon, the head of Happydale Insane Asylum, where some of the characters eventually end up! Halloween is over, but rent (or buy!) ARSENIC AND OLD LACE anyway. Be prepared to laugh!