iDummy uses DAF technique trying to affect user voice in a fun way.
Just connect your headset (earphones & mic.), press start and try to speak normally... if you can! You will see it is not as easy as it seems.
Configure voice delay with the slider, and background sound with the switch selector, to perform best voice synchronization, and HAVE FUN!
You can watch the DAF effect at youtube videos:
http://www.youtube.com/watch?v=GeQHpBVgwEk
There are more DAF apps, but iDummy is the best!!
Find more interesting apps at http://iwazowski.com/