I figure that since my friends and I do this so often, a lot of other people must do it too.
You take an airline like Southwest and rename it Southworst.
Or a restaurant or fast food place: Taco Bell becomes Taco Hell or Taco Smell, Acapulco becomes Acapuke-oh, etc.
Or take a store and French-ify its name: JC Penney becomes Jacques C. Pegne, while Target becomes Tarzhet. (Or change it some other way.)
And so it goes.
What have you renamed?