Explorateur on Tremont Street may seem like an unassuming café from the outside, but they’ve got more going on than coffee and cookies (translation: there’s booze). To celebrate their slightly incognito vibe, on Thursday, September 13th, they’re transforming their private dining space, the Library Room, into a secret speakeasy for a proper Prohibition Party. From 7:00 to 11:30pm, dust off your fedora and dancing shoes to enjoy of-the-era cocktails and snacks from the kitchen along with live music from the Boston-area indie folksters of Young Frontier. The password is a crisp $10 bill, and unlike an actual speakeasy somebody will be checking IDs at the door, so be sure to have yours. Grab your tickets here.