{Cathar's Crusade}on yourself, then cast {Sudden Disappearance} on yourself. And there. All your creatures get +1/+1 counters equal to the number of creature you have on the field. (Use at your second main phase for maximum efficiency)
Unless of course your sudden disappearance would have been better used to remove your opponent's creature to swing for lethal. I can see a game being lost because up didn't swing when you have a chance. Good combo though if the conditions are right. It could definitely tip the odds in your favor if you don't have enough to swing lethal and the opponent is matching you in terms of creatures.