Continuity mistake: In season 5 episode 8, Marshall and Ted are playing on an Xbox 360 Console. If you look carefully, you see that Ted's Xbox controller has no batteries in it, yet he is playing the game with Marshall, and then a few scenes change and so do the batteries. Scene 1, 12 minutes and 23 seconds: Marshall's remotes has a battery in while Ted's is out. Scene 2, 12m 40s: Marshall's Xbox control has no battery in. Scene 3, 12m 51s: Marshall's battery is back in the controller. Scene 4, 12m 58s: Marshall's battery is out again. Scene 5, 13m 44s: Marshall's battery is back in.Rockncyber
Continuity mistake: When Lily is selling her favourite dress and is saying how she got a two syllable damn, the flashback shows her with the hairstyle she got after Coming Back from San Francisco, even though she said it happened in 2004. She should have had her shorter, lighter coloured hair. (00:15:10)
Continuity mistake: When Lily goes to the bar with her friend Michelle, Barney says "I want her around all the time." It then cuts from Barney to Lily's slightly shocked looking face, obviously from a previous cut/scene change, sitting at the table with them - she should still be walking to the bar with Michelle.
Continuity mistake: When Robin leaves to get Battleship, Barney thinks they're going to have sex, whips his belt off, and throws it on the floor. When Robin returns, he's neatly folding his pants and draping them over a chair, and his belt is still threaded through the loops. (00:16:20)