On a whim, I attended a pop up dinner by Tree House earlier this month. For $45, we got a 5 course meal and all the sake we could reasonably drink, prepared by chefs Kevin O'Connor and guest chef Adam Pechal.
The dinner I attended was held at Old Soul's Alley location at 17th & L. We sat in a long communal table and ate family style. It was a great meal and a great experience.
The food was styled after an Izakaya, which is generally Japanese food which you would eat while drinking beer. We made our own hand rolls, ate skewers with chicken thighs and kidneys, had pork cheek, and other delicious courses. Nothing was too adventureous, but it's probably not what you would have eaten that night otherwise.