"NO MONEY MEANS NO ANIMATION!"

Perhaps the most infamous instance of the fourth wall breaking happens after Mung, Chowder, and Schnitzel run out of money in "Shopping Spree". Mung points out that they don't have any money left for the animation budget...at which point the show cuts to the live-action voice actors of the four main characters—Dwight Schultz, Nicky Jones, Tara Strong, and John DiMaggio—sitting in the recording studio lamenting the lack of cash. They then decide to hold a car wash to raise the funds they need, and after a minute of live-action footage of the quartet spraying down various vehicles, Schultz/Mung announces that they've made enough to get the animation back; the show becomes a cartoon again.

Example of:
Medium-Shift Gag