Four precious hours

We've got a use-or-lose-it type of vacation here at work and yours truly has four very precious hours I must use before July 1.  It's already the 13th, and I have to be strategic about this given my underling is going on vacation next week and I have to do all of his work while he's gone.

So, I need you ladies to give me a good suggestion!  Do I take the afternoon off on a Friday?  Do I leave early or come in a hour late for four days?  This is kind of like having some special end of fiscal year candy.