As far as we can recollect, Midwest has not in the past advertised their weekend deals. They have had them in the past, but not posted on their Web site (indeed, other airlines, such as Northwest, frequently have weekend deals that they don't post online, often matching United and American, which typically do list all their deals on their sites). Anyway, this week Midwest is indeed listing a bunch of weekend fares for travel this weekend or next. And what's especially cool is that you can leave on a Thursday or Friday and return on a Sunday, Monday or Tuesday, whereas most weekend fares require leaving on a Saturday and returning the following Monday or Tuesday. Purchase by February 23 or until seats are sold out.
See deals from Kansas City