Beeyou (pronounced "bee-yoo" or "byoo") is a sound effect turned adjective from the popular Nickelodeon "Nicktoon" Doug. Usually used to describe something terrible unfortunate or extremely distasteful, the pronunciation of the word varies depending on the effect one is going for.
The word is popular among Central Connecticut State University students, specifically those in EHBMTG.
Jes: So we found this girl passed out in the bathroom last night.
Rob: (laughing) Beeyou.
Kelly: The alarm clock fell on Rich's head and ended up waking James up!
Dave: That's pretty Beeyou.