Last one to post in this thread wins!

Do it with a big smile on your face. Keeps them wondering.
I turned in my key at the end of April, didn't say a single word, just dropped it on the manager idiot's desk and walked away.
Started the new job on May 2. Making far more $ and far less stressful.

I did similarly when I retired. Having seen how they treated previous employees that gave their notice, I kept quiet. On my last Friday, I went to the office for my paycheck, turned in my keys, "You have my mailing address you can mail the remaining check." :D