My favorites are Calvin Trillin's "tummy trilogy" of books about his all-encompassing obsession with food and travel. American Fried, Alice, Let's Eat, and Third Helpings.
David Sedaris's stuff is giggle-out-loud funny on every page, and close enough to the truth to be considered "memoir". Naked, Me Talk Pretty One Day, and Dress Your Family in Corduroy and Denim are where to start.
English music journalist Stuart Maconie has written a couple of hysterical books about travel in the real England, Pies and Prejudice: In Search of the North and Adventures on the High Teas, and an even better memoir of his life as a music obsessive, Cider With Roadies.
My real favorites are the series by the inimitable and criminally overlooked critic, novelist, and intellectual Clive James. The first, Unreliable Memoirs, tells the story of his hardscrabble early life in Australia; the second, Falling Toward England his arrival in England and bohemian days in sixties London. Later volumes are perhaps a letdown in the riotous comedy department, but well worth it for the James fan, though I might steer you towards some of his other books instead. Still, these early ones are among the self-deprecatingly funniest, truest ever written.
James's compatriot Barry Humphries has a great deal more than just Dame Edna Everage in his resume. He's told his life story a number of times, but probably best in My Life as Me. Dame Edna has her own biography, but that might be a bit too purple-haired to qualify as a memoir, hysterical as it is.
Stephen Fry is one of the funniest fellows in the history of the world, and among the most erudite and candid. Moab is My Washpot is name of his early autobiography. There's a second volume, The Fry Chronicles which I haven't read yet.
I'm not sure I'd call the many and various short pieces of S. J. Perelman "memoirs", though there is a great deal of memoir in them, but they are certainly charming and insane. He wrote Marx Brothers scripts, if that gives you any idea. You might dip into The Most of for a taste, and carry on if you like it.