I think the title is pretty self-explanatory. Usually we would also make a scary face and Attack Hands to go along with the "RAAARRRR." As you can imagine, it was a riot. Good times were had by all.
One day we took the scares to the next level. David and I made a man out of newspaper, and when we were done admiring him, we stuck him in the shower:

We succeeded in scaring the pants off not only our little brother Matt, but also ourselves. We constantly forgot he was there.
These are the good kinds of scares.
The bad kind is when you agree to meet your visiting teacher, who is in her 50's, outside her apartment late at night so she can let you borrow her key to the community hot tub because you lost your own, but then you get there early and hover outside the door, which is cracked open, and you can hear her rustling in the coat closet for her coat, and then you timidly tap on the door just as she is opening it and she throws her hands up in the air and screams at the top of her lungs. And she is wearing her nightgown.
No good.