Some of these're really vanilla and obvious, but I like 'em...
Necropotence + Ivory Tower = Happy Fun
Mortuary + Fecundity + Altar of Dementia + Mongrel Pack = Refill hand, mill eight cards from opponent.
Sorceress Queen + Nettling Imp + Sengir Vampire = Rigidly old school.
Dark Ritual + Hypnotic Specter =
Breeding Pit + Lord of the Pit/Minion of Leshrac = Soooo old school, sooo scrubby, but a lot of fun anyhow.
Portcullis + 2x Maze of Ith = Scrubby as well, but highly entertaining.
I wuv black.