[Cap'n Crunch]

To me, ATHF and The Brak Show look like they are animated in Flash. If they aren't, you could create something exactly like it in Flash.

From ATHF.com: The characters were all created as layered Photoshop images. The audio and animatic is cut using Quicktimes (short film cuts) of the original characters using a few different animation and design programs. All of the actual animation steps are done at the Williams Street studios under the creators supervision.

I'm pretty sure it is Flash.