Band or DJ? - S8-E13
Revealing mistake: When Jason Segal (Marshall) gets blasted in the face with confetti, you can see him squint his eyes in preparation for it.
Continuity mistake: When they are watching the music video on the small screen on the table, there is a bottle of JT Cola next to the screen in the close ups. When it goes to a wide shot, it is suddenly replaced by a beer bottle. However, in the previous shot before the commercial break it is a JT Cola bottle in the same spot as the beer bottle.
Chosen answer: She was finally shown at the very end of the last episode of season 8, continuing into season 9. The actor's name is Cristin Milioti: http://www.imdb.com/name/nm2129662/.
Knever