Rock on, dude. I applaud your courage for doing something like this, and on Madness Day no less.
As for the toon itself, I would say this is pretty solid for a first attempt. Let me tell you, I have definitely seen worse. The faces you stuck over the madness dudes were pretty funny, and worked well for something as short and simple as this. But if you do end up continuing it, I'd at least have them change expression every now and then if you keep rolling with that idea.
Here's something else you could try. Go and watch a couple of the latest Madness episodes again, and pay attention to the characters when they're idle. Very rarely will they be completely static. There's always some form of movement going on, even if it's just breathing.
Another thing. I don't know what FPS you animated this at, but I seem to recall that Krinkels animates at 60-something? Or maybe it was 50-something... Either way, I would try stepping up your frame rate to allow for much smoother, less robotic-looking motion for the characters. I haven't done anything higher 36 myself, so I can only imagine how difficult it probably is dealing with that many frames. But, it'll be worth it in the end, I'm sure :)
Just thought of something else. GUIDE LAYERS and EASING. These are two tools that would help you immensely toward the goal of smoother, more realistic animation when using a lot of tweens. My last bit of advice to you would be to pop open a tutorial here on NG and get reeeeeaaaaaaal familiar with those concepts.
Actually, I lied. One more thing: Camera usage. Zooming in/out when the main character enters/exits a room is a good start, but you can do so much more with the cam that just that. Move it around during the action, shake it a bit, zoom in on spots where the character is looking, etc. You did a nice job on that in the last scene; more of that kind of camera movement makes for a more dynamic and engaging animation.
/)