In the episode "Prom Queen" [Season 2, episode 20] Puck accompanies Artie on guitar while Artie sings an apology to Brittnay ("Isn't She Lovely"), later in the episode, Puck and Artie sing at Junior Prom ("Friday").
They (Sam, Artie, Puck and Mike) sing the song in the episode 'Comeback', which is the thirteenth episode of season 2.
Season 1, episode 11, Hairogrophy
Puck (Mark Salling), Sam (Chord Overstreet), and Artie (Kevin Mchale) sang Rebecca Black's Friday in the Prom episode of Glee.
Season 1, Episode 18 - Laryngitis
Finn, Puck, Kurt, Artie, Matt, Mike and Will (aka Mr. Shuester).
Isnt She Lovely - Artie Friday- Puck, Artie, Sam Rolling in the Deep- Rachel & Jessie St.James Dancing Queen- Mercedes & Santana
Episode 8 - Mash-up
Episode 13
Episode 3, Acafellas.
Laryngitis episode 18 of season 1
Everytime Puck gets Finn's girlfriends pregnant.... JK, mostly at Sectionals. Last episode in season 1.
No, In that episode Puck is in Juvie. Mark Salling however, the actor that play's Puck was off working on his Music Career.