Season 1 Episode 13: Happy Valentimes! Tracy and Angie role-play, Liz meets Flower Guy, and the TGS staff plays a few rounds of Marry, Boff, Kill.
Season 3 Episode 11: Jon Hamm! Other stuff happens, too.
Season 4 Episode 13: Liz has oral surgery, attempts a Jamaican accent, and tries to make out with what she thinks is Bon Jovi. Don Cheadle on a bed of rice!
Season 5 Episode 14: In which we learn that Matt Damon is the male Liz Lemon.
Season 6 Episode 6: The infamous IKEA episode! A must-watch before a couple's trip to IKEA. Also, Jack discusses "Jeter's legs in those pants".
All on Netflix Streaming
Season 1 Episode 12: Michael gives a Valentine's Day toast which causes his family to act-out even more than usual.
Season 2 Episode 10: I find the Bullet character exhausting in this one, but Tobias' double entendres are priceless.
Both on Hulu
Season 1 Episode 15: The perils of the naked-under-the-trenchcoat move.
Season 2 Episode 14: Gloria wins Valentine's Day!
Parks and Recreation
Season 2 Episode 13: Will Arnett as a creepy MRI technician!
Season 4 Episode 14: Chris DJs, Ann finally uses her car-charger curling iron.
Both on Netflix
Any other favorites? I'm sure I'm forgetting tons of them!