1.  I am currently out of the office at a job interview and will reply to you if I fail to get the position. Please be prepared for my mood.

2. You are receiving this automatic notification because I am out of the office. If I was in, chances are you wouldn't have received anything at all.

3. I will be unable to delete all the emails you send me until I return from vacation. Please be patient, and your mail will be deleted in the order it was received.

4. Thank you for your email. Your credit card has been charged $5.99 for the first 10 words and $1.99 for each additional word in your message.

5. The email server is unable to verify your server connection.  Your message has not been delivered. Please restart your computer and try sending again. (The beauty of this is that  when you return, you can see who did this over and over and over...)

6. Thank you for your message, which has been added to a queuing system. You are currently in 352nd place, and can expect to receive a reply in approximately 19 weeks.

7. Hi, I'm thinking about what you've just sent me. Please wait by your PC for my response.

8. I've run away to join a different circus.

9. I will be out of the office for the next two weeks for medical reasons. When I return, please refer to me as 'Lucille' instead of Steve.

There are a few there I'd use