I like this one...

1. Grab the nearest book.
2. Open the book to page 123.
3. Find the fifth sentence.
4. Post the text of the sentence in your journal along with these instructions.
5. Don't search around and look for the coolest book you can find. Do what's actually next to you.

"This is true up to the energies of pulverizing matter into bits as small as a billionth of a billionth of a meter, the current technological limit."

The Elegant Universe by Brian Greene
Non-fiction all about string theory and quantum physics and such, which I have been occasionally reading through since summer.  VERY slow going, but fascinating all-the-same.