This is one of the best ideas I've heard about in a long time:
The Puppy Channel was a short-lived American cable television channel whose programming consisted entirely of video footage of puppies.
It's a pity it didn't survive, although it apparently wasn't THAT short-lived, either: it did broadcast for four years, according to Wikipedia, and only folded in the end with the bursting of the dot-com bubble in 2001.
Today, there's still the annual Puppy Bowl (thanks to altivo.dreamwidth.org for pointing this one out to me); the first five Puppy Bowls are apparently available on DVD, too, although some are OOP, and there's also the Puppy Games '08, a puppy version of the olympics, and a DVD called Puppy Party.
And of course, there's Youtube! Check out this cute bunch, for example:
Here's another cute puppy video; and of course, big pups can be very cute, too. ^^ (And if you still need further proof of THAT, I'll also submit shadow_stallion's pup — a very cute snowdog who's very happy to have snow right now. ^^)
Seriously, if you ever feel bad (sad, stressed, whatever), just watch a video of some cute puppies romping and playing, and you'll feel better in no time.