Sonic Drive-In is “shaking” things up again by bringing back its very popular late-night offer. The burger chain’s daily half-price Happy Hour on drinks and slushes from 2 p.m. to 4 p.m. does not include shakes. However, if you’re willing to wait a few hours, you can enjoy an even sweeter treat and still save a few bucks. For a limited time, after 8 p.m., all shakes are 50% off. Choose from 25 sweet, delicious flavors. Each shake is topped with whipped cream and a cherry, of course. Sonic has changed the shake menu and divided it into two types — Classic Shakes and Master Shakes. The latter are slightly higher in price. There’s no limit, so everyone can get a “shake down” without breaking the bank.