This week’s episode of ABC’s Castle opened with the titular character rocking out in Guitar Hero 5 to “Dancing With Myself.” Nathan Fillion (of Firefly and Dr. Horrible fame) showed off some sweet rock moves to earn himself even more geek cred — as if starring in a cult sci-fi TV show and voicing a Halo character weren’t enough.

If you’re not watching this show, you really ought to be. It’s smart, funny, and unpredictable, and it features some really excellent performances, especially from Fillion and Molly C. Quinn, who plays Castle’s daughter. There’s just one problem: This week’s episode was by far my least favorite since the show launched last season. So, watch it to see Fillion rock out, but then watch another to get a sense of what the show is like when it’s firing on all cylinders.

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