By using these words you can end any conversation, denote the finish of a project, or excuse yourself from any situation with authority. It's almost like... magic.
Phrase used to 'close' the Marauders Map, making it blank and causing it to appear as a normal piece of parchment until the words "I solemnly swear I am up to no good" are spoken, which activate it. (Part of the Harry Potter book series)
"As Sirius Black noticed Snivellus Snape come around the corner, he cried 'Mischief Managed' and the Marauders Map became blank."
A new, more hip way to be owned . Management, while having the same connotation of complete loss or failure, happens more frequently in the real world than its virtual counterpart, ownage.