Happy Birthday Song Contest Mordecai and Rigby are determined to win a happy birthday song contest so they can get a year's supply of cake. Details Casts Videos Galleries Posters Season Lists Title Happy Birthday Song Contest Genres Animation Comedy Release Date 2015-02-19 Episode Runtime 00 Hours 11 Minutes Season Number 6 Episode Number 19 Production Companies Cartoon Network Studios J.G. Quintel... Mordecai / Hi Five Ghost ... William Salyers... Rigby (voice)... Mark Hamill... Skips (voice)... Sam Marin... Benson / Pops / Muscle Ma... Regular Look at Regular Show (Clip) Original Size (1920x1080) Original Size (1280x720) Original Size (3840x2160) Original Size (1920x1080) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (1600x900) Original Size (1280x720) Original Size (1920x1080) Original Size (2973x1673) Original Size (1920x1080) Original Size (1920x1080) Original Size (1920x1080) Original Size (1920x1080) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (3840x2160) Original Size (1920x1080) Original Size (1920x1080) Original Size (1000x1500) Original Size (2000x3000) Original Size (1000x1521) Original Size (2000x3000) Original Size (2000x3000) Original Size (2000x3000) Original Size (2000x3000) Original Size (1708x2562) Original Size (680x1000) Original Size (641x938) Original Size (2000x3000) Original Size (960x1440) Original Size (1708x2562) Original Size (667x1000) Original Size (1000x1500) Original Size (552x827) Original Size (680x1000) Original Size (832x1280) Original Size (600x900) Original Size (1200x1800) Original Size (2000x3000) Original Size (1708x2562) Original Size (1708x2562) Original Size (1856x2644) Original Size (667x1000) Original Size (2000x3000) Original Size (1200x1800) Original Size (720x1080) Original Size (720x1080) Season 1 12 Episode(s) 2010-09-06 Season 2 28 Episode(s) 2010-11-28 Season 3 39 Episode(s) 2011-09-19 Season 4 40 Episode(s) 2012-10-01 Season 5 40 Episode(s) 2013-09-02 Season 6 31 Episode(s) 2014-10-09 Season 7 36 Episode(s) 2015-06-26 Season 8 31 Episode(s) 2016-09-26