SB Nation now has a channel on YouTube, with over 30 original videos appearing every week. All sports are covered, though since this is a baseball blog, here's a couple baseball-specific series:
Rob's Mailbag (Baseball -- New episodes on Wednesday): Get smarter about baseball with Baseball Nation's Rob Neyer. In Rob's Mailbag, Rob takes questions from viewers every week and breaks them down in absurd (and extremely entertaining) detail. Essential viewing: http://www.youtube.com/watch?
The Petey and Lomo Show (Baseball; comedy): It's our first reality show and we followed Miami Marlins players Bryan Petersen and Logan Morrison (Petey and LoMo, to the initiated) as they tried to find ways to fill the boredom that is Spring Training in South Florida. Essential viewing: Marlins Off The Hook (i.e. Master-baiters): http://www.youtube.com/watch?