None actualy, they never play anything.
My step-father however plays Civilization and Heroes of Might and Magic from time to time.

my mother plays: wiifit & sims2

my father plays: f1 '97 (ps1) & duck hunt

Dad: Every single Command and Conquer (Red Alert 1/2/3, Tiberium Wars, Generals, Renegade), Age of Empires 1/2/3, The Witcher, SWAT, Medal of Honor (all versions)

Mon: Not much anymore, she used to like Solitaire, Picross DS and a Sudoku game. And Puzzle Bobble in Mame or in arcades

well my mom has a hard time deciding. I asked her, said ok, you can tell me a top 3 instead.

In no particular order:

Sacred(both)
Diablo 2
Neverwinter nights.

Worthy mentions:
Final Fantasy X
Heroes of might and magic (3, 4 and 5)

I got no clue if my dad ever played anything lol.