Press ctrl+shift+p to put on a pumpkin mask. Replaces any helmet or whatever you have on. Unlike the pumpkin costume in the shop, you can't change the pumpkin mask expression and no other accessory comes with it.
Press ctrl+shift+r. What can randomization do for you? Besides randomizing your character, it has a chance to give you these hand-held items; a football (press spacebar to activate it's special action), a basketball, a mobilephone and a tennis racket. It's advisable to have the costume-saving-mirror-thingies to make sure you have saved your current outfit before randomization and to save the hand-held item you have acquired.