There are some cool ass shows on discovery channel still. Mainly Dirty Jobs but there are others too.
One of my favorite series on the History Channel was that Barbarians series. Where it showed the history of Vikings, Huns, Mongols, Saxons and a few others... I think there was also a Barbarians 2 series. Also the Dark Ages was a pretty good one also. That kinda stuff is awesome to watch high or not.
I too notice myself watching less and less History channel, what a shame. I really used to like that channel too. Corporate whores lol. The only good shows on History channel are modern marvels and the universe i guess.