There are five artists with this name: 1. A popular British alternative band active from 1993 to 1998 2. An active dubstep/techno producer from Coventry, England 3. An experimental hip-hop musician 4. A garage rock band from Oklahoma formed in 2008. 5. 90s emo / post hardcore band from Staten Island, NY. Later changed their name to Serpico after getting paid off by the English band. 1. Sleeper was a Britpop group which formed in 1993 in Manchester, England.