Lucy In The Sky With Microdiamonds

Yep, yep, it was the microdiamonds that did it, mate. Wiped out all the big mammals in North America in the geological equivalent of a microsecond.
Actually, it wasn't the diamonds, according to this theory, that caused the disaster. But they are evidence of the massive assault from space of mini-comets, and they're embedded in the arctic ice of 12,900 years ago. For some reason, the people who roamed the North American continent at the time, the Clovis, previously believed to have been such diabolically good hunters (spears and spit, mostly) that they could wipe out whole populations of benignly stupid animals such as wolly mammoths and saber tooted cats, seem to have died out or wandered away at the same time, probably looking for food.
Oh, anyway, I haven't been so excited by a Nova show since the series on string theory a few years back.

Nova investigates a provocative new theory that suggests the extinction of more than 34 types of large prehistoric mega-creatures, such as the saber-toothed cat and woolly mammoth, was caused not by climate change or the arrival of the first human hunters, but by the massive breakup of a comet over the Great Lakes region at the end of the last Ice Age, some 12,900 years ago.

As if that weren't enough, Frontline followed with a surprisingly good take on health care reform, with most of the insurance industry saying, sure, we'll insure everybody as long as you make it a mandate.
That was Hillary's proposal. Barack wasn't going that far. Can he pull it off? News at 11.
This is not the reason I have a TV, but it's the reason I'm glad I have a TV. Beats the 12" monitor on my kitchen counter.
But yeah, you can see them online. PBS is nothing if not cutting edge.