Here's an outrageously hilarious commercial for Tide.
Conceived by Leo Premutico & Jan Jacobs (when they were ECDs at Saatchi & Saatchi NY, pre-Johannes Leonardo), it features a talking stain - the real star of the ad.
Simple idea. Killer execution. Memorable end result.
The above also features the best use of gibberish in an ad ever.
As for best use of gibberish in a feature film, this comes to mind.
This scene makes me fall off my chair - everytime!