The concept is to mashup something along the lines of a public apology, a commercial, a pandering politcial speech or anything you’d like to mock for the public good.

Here are the steps-

1. Pull the audio as an mp3 from YouTube using Zamzar or something similar.

2. Import it into audacity or any audio mixer you have

3. Import the music you want to layer behind the audio

4. Edit to taste

5. Upload to soundcloud

6. Share the link