Just found a NYT article about that previous attempt to draw students in at off-peak hours: http://www.nytimes.com/2003/11/09/edlife/1109GRT.html?pagewanted=all
It was back in 2003, when UO had fewer classroom buildings, to alleviate space shortage and student complaints about not being able to take necessary courses to graduate on time. Now there's plenty of space but it's not being used and students choose to skip in order to have more play time:

"* A variety of campus-specific discounts are available . . . . And with a squeeze on its classroom space during the school year, the University of Oregon gives a discount to students who take classes later in the afternoon -- 15 percent off ones that begin after 3 p.m. and, starting in January, at 8 and 8:30 a.m. Courses cost $92 a credit hour, so the discount reduces that to $78. Two such courses save almost $330 a year. "