Tuesday, Sept. 4, 2012 is National Back to School Day, and Sonic Drive-In is treating customers with half price breakfast burritos all day long. No coupon required; good only on Tuesday, Sept. 4, 2012.
Sonic still has their milkshakes at half price during their happy hour, which begins at 8 pm daily.
About Sonic (from Wikipedia):
Sonic Drive-In is an American drive-in fast-food restaurant chain based in Oklahoma City, Oklahoma, complete with carhops who sometimes wear rollerskates. As of August 31, 2010, there were 3,500 restaurants in 43 U.S. states. Sonic serves approximately 3 million customers daily.