The clues can be arranged into quadruples, one from each column, all with the same color so that they each clue the same word (which matches the enumeration). These are (in order by the first column, which is the only nonalphabetical column):
Pipes, Radcliffe, Rather, Webster → DANIEL
Cottage, Cream, String, Swiss → CHEESE
Banff, Medicine Hat, Red Deer, Spruce Grove → ALBERTA
Cave, Channel, Mobile, Time → BAT
Impostor, Paycheck, Screamers, Second Variety → DICK
Captain Gannon, Reverend Whirley, Sergeant Friday, Streebeck → DRAGNET
HIV Gene, Joke, Silence, Vomit → GAG
File, Nanny, Travel, Water → GATE
Collie, Line, Patrol, State → BORDER
Crab, Delicious, Empire, Fuji → APPLE
Chandler, Mesa, Peoria, Tucson → ARIZONA
Democratic, Pornographic, Sad, Union → BLUE
Besbriss, Constable Fraser, Detective Vecchio, Huey → DUE SOUTH
Cary, Land, NSF, Ulysses → GRANT
Illness, Insect, Irritate, Microphone → BUG
Civic, Double, Heavy, Jury → DUTY
Attractive, Blond, Carnival, Just → FAIR
Babar, Dumbo, Hathi, Horton → ELEPHANT
Dead, Game, South, Zone → END
Duct, Sent, Stable, Tact → CON
Breed, Eyed, Oneself, The Rubicon → CROSS
The colors alternate red and black by row. The answers all begin with letters A-G. This clues a game of Connect Four. Ordered by the first row (which is not alphabetical), the players alternate dropping pieces into the column corresponding to the answer. For example, Red begins by playing in the middle column D (for DANIEL). Red wins. Take the four answers which form the four in a row. They are ALBERTA, BORDER, CROSS, DUE SOUTH. This clues the answer, MONTANA.
2006 MIT Mystery Hunt