This is where the gang attends Marla's movie screening in the season three episode "Women on the Verge"
Exterior: Griffith Observatory, 2800 E. Observatory Rd, Los Angeles CA
Interior: Vista Theatre, 4473 Sunset Dr, Los Angeles CA
Note: Thanks to Lindsay at Iamnotastalker.com for noticing the different interior. The Google link is for the Vista, and the Bing link below is for Griffith Observatory