Yesterday, we delved into seasons one through four of Buffy the Vampire Slayer's birthday episodes. Let's just say you really, really don't want to celebrate Buffy's birthday with her, as catastrophe, drama, and heartache are always center stage.

Season Five, episode 13, "Blood Ties"
Buffy's 20th birthday goes no better than the previous ones. "Blood Ties" is all about how Buffy and Dawn share the same blood, "Summers blood," even though Dawn was created by monks to be The Key. Yes, it was a somewhat syrupy solution to Dawn's incessant whining in this episode, but it is so important for the resolution to the season, and the defeat of Glory, the Big Bad (Buffy can die instead of Dawn to save the world. Again.).

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When you want to conjure up some ratings magic, a special guest star always helps. And if you can get the star to commit for a few episodes during May sweeps, well that's even better. With that in mind, the CW has signed Michelle Trachtenberg for a multi-episode arc on Gossip Girl.