The folks with the fresh baked cookies (on some flights) are having a sneak sale as of Saturday May 31.
Not only are the fares good, but there's just a one-day advance purchase. As is the case with many of the lowest fares these days, there's a minimum stay requirement. You can leave on Sunday (tomorrow) and travel through June 11. In some cases, the prices are half off previous fares. We could find this sale mentioned on Midwest's site, although they do mention this sale, which requires a 14 day advance purchase.
So check out Midwest's route map and find yourself a bargain. We've listed many of these fares in the individual city pages today.