The Dark Shadows Alphabet Game

J= Jeopardy which Barnabas was in when his coffin was in the open in the cellar

K is for Keene Curtis (voice of Judah Zachary)

L is for longevity, which could apply to the show's popularity or to some of its immortal characters.

M is for Minerva Trask

N is for Julia's notebook.

O is for odious.....which I think describes all the Trask men perfectly

P is for Prayers by various Trasks, which must have made the Almighty want to throw up.

Q is for the quizes that David had to take when he was being tutored by Vicki or Maggie

R is for the rectory.

S

Segue

T is for telephone.  Flies prefer black ones.  Ghosts prefer old ones.

U is for upper crust New England family. 

V is for Vala Clifton, who played Maude Browning.

W is for the woods, which is where most of the bodies ended up.

X is for Xander, which they could've called Alexander for short. (Cut me some slack. It's X.)