This Toy Stories photograph series of animal figurines and funny captions by Aled Lewis is adorably amusing. Two favorites (but you should check them all out, and you can buy a whole book! I want it):
If one is somehow still feeling blue after that, there's this 50 cutest things that ever happened page. This baby elephant face plant and stuffed toy look-alike puppy are my favorite.
This is the clincher for me though: Ginger in Peter's glasses. Just remembering how much I cried from laughing so hard while he was taking these photos is enough to draw a giggle every time I see them. (And this is yet another example of how she is the world's most tolerant dog.)
And of course there is a whole YouTube trove of cute animal videos, like Lala the penguin who wears a backpack to go shopping for his own fish or the sneezing baby panda that scares its mom, for a really tough day. Any other suggestions for me?