While I've always gotten a chuckle out of the Bulwer-Lytton contest, the fact that all of the entries are made up takes some of the fun out of it for me (though see this page on the Bulwer-Lytton site which contains actual published gems such as ""She stuck to his prime-grade A tush like shrink-wrap to a rump roast.").
The Bookseller/Diagram Prize for Oddest Title of the Year on the other hand, has only bonafide publication titles competing. This year's entries (see the lower right-hand corner of the page) include a range of future classics such as How Green Were the Nazis? and The Stray Shopping Carts of Eastern North America: A Guide to Field Identification. And the lists from previous years were enough to make me laugh out loud even today, a Monday made worse by the need to "spring forward" this weekend.
My personal favorite is probably The Art and Craft of Pounding Flowers: No Paint, No Ink, Just a Hammer! but that may just be a reflection of my mood today. (A thanks to Nick for forwarding the URL.)