Another classic from the old days. My brother and I made tons of these MockMashes, mostly arranged by him. Couldn't think of a funny outro for this one, though :Þ
MuseScore for the score, Pro Tools for the audio, East West Pianos for the piano, my voice for the voices :Þ , QuickTime for the screen recording, iMovie for the video editing, and RU-vid for the uploading. Most of these could be substituted for ones you're more familiar with :)