Joe McReynolds
Google
You've probably already heard the concept of the place if you've come here -- it's a bookstore that costs about 15 bucks to enter. But in practice, it's more like a comfy private library (everyone is mostly silent) that will sell you the books at MSRP if you want them, with a cozy cafe attached. How much you enjoy it will depend a lot on whether the selection of books is up your alley -- there's a lot of design, art, architecture, photography, urbanism, etc -- and whether you speak Japanese or not will radically change your offerings (though there's plenty in English within the aforementioned categories if you don't). In my research field, I found a few really cool books I'd never even heard of before, so the trip was totally worth it to me. YMMV, not something you absolutely need to experience but it sold me on the value of it, even though I went in skeptical.