They play the Happy Days/Grease card a little heavily at Issaquah?s XXX Root Beer Drive-In: burgers named for cars (the ? ?58 Impala? is a half-pound bacon cheeseburger) and a relentlessly catchy AM-radio soundtrack (Chuck Berry, the Cowsills). But we love it because it feels like an authentic hangout. Its orange and yellow picnic tables are just the place to meet friends or take the family on a summer Saturday night?as they have been for decades; the restaurant opened in 1940 and has been in its current location since 1968. Vintage-car enthusiasts like to show off their gorgeously maintained vehicles at XXX too, adding to the ambience. We don?t say it?ll be cheap. The burger-and-fries baskets are all upward of $8, and a mug of root beer?scrumptious, with a home-brewed taste, though on the sweet side?is $2.59. But it?s worth it. ?Nothing that you eat or drink here is good for you,? says a sign. Well, maybe not nutritionally, but definitely emotionally. ?Gavin Borchert 98 N.E. Gilman Blvd., Issaquah, 425-392-1266, triplexrootbeer.com