Thanks to a flashback video about LA karaoke bar Dimples, you can now watch a handful of stars take the mic and seriously let loose. Prepare to be taken back to the 2000s, when Britney Spears [1] forgot the lyrics to a Madonna [2] hit, Katy Perry [3] giggled while channeling Mariah Carey [4], and Charlize Theron [5] was too sexy for her cowboy hat. That's really just the beginning — see several other stars give seemingly unrehearsed karaoke performances in the clip above, and keep the fun coming with more viral videos [6].