There are five artists with this name:
1. A popular British alternative band active from 1993 to 1998
2. A dubstep 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. 1. Sleeper was a britpop group which formed in 1993 in Manchester, England.

Read more about Sleeper on Last.fm.