Katy Perry Explained This Song To The Sun Newspaper "Vegas Gives Me That 'what The F--- Feeling.' It's Really Close To LA So One Night You Could Be Having A Beer With Your Friends And When You Wake Up You're In Vegas." Source Waking Up In Vegas Songfacts . The Song Peaked At #9 On The Billboard Hot 100 And Went To #1 On The Mainstream Top 40 Chart And The Hot Dance Club Play Chart In The Summer Of 2009.