1. Projects with realistic budgets and timetables don't get approved
2. Activity in the early stages should be dedicated to finding the correct questions
3. The more desperate the situation the more optimistic the progress report
4. A user is somebody who rejects the system because it's what he asked for
5. The difference between project success and failure is a good PR company
6. Nothing is impossible for the person who doesn't have to do it
7. Every failing, overly ambitious project, has at its heart a series of successful small ones trying to escape
8. A freeze on change melts whenever heat is applied
9. There's never enough time to do it right first time
10. You understood what I said, not what I meant
11. If you don't know where you're going, just talk about specifics
12. If at first you don't succeed, rename the project
13. Everyone wants a strong project manager - until they get him
14. Only idiots own up to what they really know (thank you to President Nixon)
15. The worst project managers sleep at night
16. A failing project has benefits which are always spoken of in the future tense
17. Projects don't fail in the end; they fail at conception
18. Visions are usually treatable
19. Overly ambitious projects can never fail if they have a beginning, middle and no end
20. In government we never punish error, only its disclosure
21. The most difficult way is, in the long run, the easiest
22. A realist is one who's presciently disappointed in the future
And thanks to TechRepublic for this:
"Only a fool tests the depth of the water with both feet" - which brings to mind one or two of the NPfIT implementations.
Links:
A collection of project management sayings
Project management jokes, humour, proverbs and laws
Do you speak "Project"? - PM Hut

There are some interesting quotes that I've never read, such as: "A failing project has benefits which are always spoken of in the future tense", and "Projects don't fail in the end; they fail at conception" (though the latter is more or less on the lines of "failing to plan is planning to file".
I have published something similar a few months ago, do you speak project, where the author defines Project Management terms in a funny way, for example:
Team - Your best friends. The group that, when asked who caused a problem, forms a circle and each person points to the left.