i've heard a lot about QI, but i've never seen an episode before, until i found about 12 or 13 longish (about 10mins) clips of episodes from the previous two series. marvellous! youtube seems to have everything!

try this for starters, and this and this, and if you like them the search tag you want is "quite interesting." (as opposed to "qi", because obviously that way you get plenty of chinese videos instead.)

and another few just for good measure.