Disclaimer: I cannot guarantee your parents reactions will be the same as mine. I'm 36 years old and they still haven't disowned me.
  1. Pretend like you're breaking into their house.
    This will likely not go well if your parents own a firearm and wouldn't recommend it. Not recommended for parents with heart issues either.
  2. Send them a picture of your brothers newborn baby.
    Highly recommend doing this within a week of the due date for the new family member. Bonus is if the picture is of a baby that looks nothing like your brother and his wife.They think they missed the birth, and that the grandchild possibly isn't theirs. It's a win, win.
  3. Hire a person dressed as a monkey to sing in a crowded restaurant or movie theater.
    This is probably overused but in my opinion never gets old.
  4. Put a mannequin in the backseat of their car.
    If they're blind enough to get in without seeing it you've won. Driving away and seeing it in the rear view is a beautiful thing.
  5. Turn their pictures into magnets
    And place them where you please. This doesn't always get noticed as quickly but when it does, it's sure to be a happy event.
  6. Bring pets home without asking.
    Okay 10 times out of 10 this will actually piss them off, but hey, one less homeless pet?