A motorist driving the highway through the Red River Valley on North Dakota's eastern plains is likely to wonder where the valley is. The landscape seems flat enough to carry a rolling cue ball into Grand Forks. Nothing but nothing extends as far as the eye can see, with only an occasional copse, farm or highway overpass to relieve the monotony. But these days the traveler is apt to be jolted awake by an incongruous sign that suddenly pops up out of the landscape: "Stay in North Dakota—Custer was healthy when he Left." Down the road a stretch comes another billboard: "Enjoy North Dakota—open year round." In the western part of the state yet another board offers the mock warning, "Stay in North Dakota—Montana closed this week."

The billboards, 30 in all, are the witty outcome of a collaboration between a newspaper columnist, a billboard salesman and the state's new tourism director. Last July, Lloyd Omdahl, a 55-year-old political science professor and director of the Bureau of Governmental Affairs at the University of North Dakota, Grand Forks, used his syndicated weekly column to propose billboards with epigrams poking fun at North Dakota and neighboring states. Dean Anderson, 36, a former student of Omdahl's and sales manager for the Newman Sign Company, which owns 2,500 billboards statewide, liked the idea and offered to donate vacant boards. Jim Fuglie, 38, the tourism director, gave the go-ahead but reserved the right to edit the messages. He says, "The best one that didn't make it was 'Welcome to North Dakota, led by sinners, populated by saints"—the Democratic governor is George Sinner. "But the Governor suggested a good one," Fuglie says: 'Welcome to North Dakota—Many are cold, few are frozen.' "

The laconic barbs are popular with the billboards' intended audience. "I love 'em," says retired saleswoman Lamoine McLean of Grand Forks. "I get lots of comments from our friends driving in from Montana and Minnesota." The signs have even improved business. A trucker checked into a motel one recent frigid night and told the clerk, "K must be bad weather, if they've closed Montana." She laughed and said, "No, that's just a joke." He shrugged and said, "Well, you got my 21 bucks!"