I assume it was an AD&D 1e or 2e book, it had a Juggler or Jester variation of the Thief with a Marotte who was adept at throwing and catching, a section on blood magic that discouraged players from being murderous psychos and implied it was mainly a mechanic for villainous NPCs, a section on social class that included the monthly living cost to maintain that social class...
I'll add more details as I remember them, I know this is a shot in the dark but I can't get it out of my mind and I can't find any leads on it online.
I figure if anyone would know what I'm talking about they would be on this forum...
This sounds a little like 1E's Unearthed Arcana, which included a Thief-Acrobat class, and a little like 2E's Player's Option: Skills & Powers, which included a Jester kit. But neither one completely fits with the information you've provided.
Lets see.
Possible sources.
Best of Dragon IV is a likely one.
This had the Jester and the Death Master.
The 2e Bard or Rogue book had a Jester kit I believe. One of my players has both, but not on hand to check.
Jester first appeared in Dragon issue 60.
I found it!
Adventures Dark and Deep.