With the advancement's of today's Technology, it is possible to alter sounds, voices and even video in Real Time.
Opera tennis, involves specially altering Tennis matches to make them more dramatic. For instance, a famous evil mastermind's voice could be applied to a Tennis Player's voice during Match.
Choices include, Darth Vader, Planton (from Spongebob Squarepants), George W. Bush, and other various fictional and non fictional Characters.
Opposite roles in Characters might be: Luke skywalker, Spongebob Squarepants, John Kerry and more Do-gooder type characters.
Sounds effects could be applied to every move a Player makes. Like the swing of a Tennis Racket could be a suped up whoosh, followed by the hit of a Tennis Ball hitting the Racket could be a small explosion. Followed by a whistle and either a larger sounding explosion if the ball hits the ground, or a richoeting type sound when the opposite Player hits the Ball back.
A database of Catch Phrases and Retorts could be played during the more intense parts of a Match. Special mood setting Music might amplify the mood.
Here's a scenario that actualy happened the other day while I played on Xbox Live: Player: I hate EvilPickles EvilPickles: don't Hate me, fear me. **Pickles applies a series of Shotgun blasts into Player's back shortly after applying the phrase** **Player dies**
Note: this was playing Halo 2, no one actually died from this scenario.