I always find it funny when agencies claim to "specialize in viral videos."
Certainly there are things you can do to encourage people to share clips (e.g., add "forward-to-a-friend" and "embed" features) and there are basic principles that lend themselves well to "going viral" (e.g., offer an incentive, make it entertaining). But it is very difficult to predict when and if a campaign will ever go viral.
So I found this clip particularly humorous.
Thanks to American Copywriter for sharing this beauty. It's brilliant.