Identify your least favorite client -- you know, the one that you hope doesn't call, the one that pays their bill late, berates your staff, and/or makes outrageous demands on your time -- and fire them.  They don't deserve your hard work (and probably aren't getting your best work anyway if you hate doing it for them).

As an added holiday bonus, let your secretary pick a client to fire too!  It is a great moral boost to everyone in the office when that one (and you don't have to limit yourself to one) client is gone.