From Daniel Finkelstein's blog in the Times
The top one is this:
"Three workers find themselves locked up, and they ask each other what they’re in for. The first man says: “I was always ten minutes late to work, so I was accused of sabotage.” The second man says: “I was always ten minutes early to work, so I was accused of espionage.” The third man says: “I always got to work on time, so I was accused of having a Western watch.”
You can read the others on his blog.