Yeah, these are a little old. But they are still some of the best internet videos out there.
Madness 1:
http://www.newgrounds.com/portal/view/58182
Madness 2:
http://www.newgrounds.com/portal/view/77750
Madness 3:
http://www.newgrounds.com/portal/view/121747
Madness 4:
http://www.newgrounds.com/portal/view/172771
Thats the official series. Good if you need an action fix.
Krinkles has sense made 2 more movies about madness. But they are not nearly as good.
Here's Madness 5:
http://www.newgrounds.com/portal/view/226896
The other one i would rather not post.