Charlie Sheen -- Throws MASSIVE Rager ... For Entire 'Anger Management' Staff

Charlie Sheen may be in a bitter battle with Brooke Mueller and the LA County Department of Children and Family Services ... but that didn't stop him from throwing a bad ass back-to-work party!

Charlie invited all his "Anger Management" co-workers over to his pad to let loose before they start shooting again this week. The show had been on hiatus.

Charlie hired "The Taste" Season 1 winner Chef K. to handle the menu, as well as a masseuse -- who handled 'Anger' co-star Noureen DeWulf. The party was organized by David Pressman events.

No strippers were present -- but Sheen did have a plane fly over his house with the phrase "KLAY-VINN! 55 HERE WE COME!"

We're told they just hit the 55th episode of 'AM' -- and the "Klay-Vinn" thing is an inside joke among the cast and crew.