Apparently, their research showed that over half of millennials (18-34 year olds) are more likely to "make a complete meal choice" (i.e. buy a combo) for lunch if it includes dessert. As such, the $5 Buck Lunch includes a sundae.
The $5 Buck Lunch is only available from 11am to 4pm at participating Dairy Queen locations and offer your choice of a 1/4 lb. GrillBurger with cheese, 3-piece Chicken Strip Lunch or a Chili Cheese Dog, plus fries, a drink, and choice of a small sundae. For a $1 upcharge, you can upgrade you sundae to a small Blizzard.
The $5 price point squares well with what's currently being offered by other fast food chains such as the $5 Buck Box at Taco Bell, King Meals at Burger King, and, of course, Subway's trademark $5 Footlong subs.
The chain also now offers an option to get their signature Blizzards in a plain or dipped waffle cone.