Conversation so far:
When did MC Hammer begin MC Hammer's music career?
Before Hammer's successful music career (with his mainstream popularity lasting approximately between 1988 and 1998) and his "rags-to-riches-to-rags-and-back saga", Burrell formed a Christian rap music group.
What was the group name?
Holy Ghost Boys.
How long did he stay with them?
CANNOTANSWER.
What else did you find interesting?
With exception to later remixes of early releases, Hammer produced and recorded many rap songs that were never made public.
Why weren't they made public?
CANNOTANSWER.

Question: Anything else interesting?
Self-contained rewrite: Besides MC Hammer's stay with the Holy Ghost Boys and some of his rap songs never being made public, anything else interesting?