surprise deadlines?

Ugh. I just had a professor give me one week's notice that I have to present a piece of writing. Nothing like a surprise deadline you had no idea was coming! :(

Instead of tackling the problem head-on, clearly, my first impulse is to procrastinate and write a blog post.
I realize I need to bite the frakking bullet and just write something to present. But...

Has anyone else ever gotten a surprise deadline? What do you do? How do you keep from letting panic overtake productivity?