With "Horrible Bosses" and "It's Always Sunny in Philadelphia' breakout star Charlie Day as host, "Saturday Night Live" earned its highest ratings in the 18-49 demo since last May's season finale.

With musical guest was Maroon 5, the episode averaged a 4.9 rating/11 share, and a 2.8/12 share for adults 18-49.

The episode was the show's best 18-49 performance since the May 21 season 36 finale, hosted by Justin Timberlake with musical guest Lady Gaga, and the best overall rating since the Oct. 1 episode hosted by another comedy breakout, Melissa McCarthy.

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As for the funniest skit of the night, the cast poked fun at the Kardashians, predictably, but the last sketch was the best, as Day and "SNL" star Jason Sudeikis played a pair of cops who're investigating a crime scene in the "Seinfeld" apartment.

Check out Day at his Columbo-y best, pretending not to know what "Seinfeld," baseball and World War II are: