Duals

Most Duals will probably be opposites(eg. antonyms) but you shouldn't limit yourself to just them.

Salt	Pepper
Odd	Even
Up	Down
Left	Right
Arrive	Depart
Big	Small
Tweedledum	Tweedledee	Through the Looking-Glass and what Alice Found There
Statler	Waldorf	Muppet Show
Positive	Negative
Day	Night
Black	White
Happy	Sad
In	Out
Grin	Grim	:)  :(
Click	Clack	NPR Car Talk (The Tappet Brothers)
Bert	Ernie	Sesame Street
Bill	Ben	Flower Pot Men
Jack	Jill	from nursery rhyme
Yin	Yang
Daytime	Nighttime
Boss	Minion