Gotta get me a copy of that one. I have admired ravens since I was a tad. Just read this at Wiki... Juvenile Common Ravens are among the most playful of bird species. They have been observed to slide down snowbanks, apparently purely for fun. They even engage in games with other species, such as playing catch-me-if-you-can with wolves and dogs.

I have seen them (and, once, a flock of ruffed grouse) play with a fox until it was exhausted but I've never seen them sliding. THAT would be cool.