ABSOLUTELY CALL IN SICK!!!!! If you need a reason, tell them you're SICK of missing the most important things in life and you're taking a mental health day! If that is a little too truthful, you could go with: "I have to stay home and clean ALL my guns today....that's what the voices in my head TOLD me to do....." Of course there's the classic: "My husband/wife and I had a huge fight this morning and I can't wait to get to work so I can call my lawyer and start divorce proceedings, and on top of that my d@#n Prosac prescription ran out two days ago too."
MMMMUUUUUUUUUOOOOOOOOHHHHHHHHAHAAAAAAAAAAAA! (evil laugh)
Seriously, don't miss this miracle of birth today....it's something you'll never forget!