If you're interested in shopping, you might be interested in Mitsui Outlet Park Iruma. As the name suggests, it's a place where you can buy branded goods at bargain prices from outlet stores.
Mitsui Outlet Park Iruma just opened in April this year. Outlet parks are not new in Japan, there's a few more surrounding Tokyo. But what makes this one special is that it's the nearest one from central Tokyo (about 40 minutes from Ikebukuro) and it's the biggest one in Japan. With more than 200 stores of international and local brands, restaurants and more, it's the most popular spot to go nowadays. More info here.
And as usual, it's summer and there a summer sale on now. I'm not much of a shopper but I managed to get my hands full yesterday.
Information about Japan in English is scarce. Here I'll try to write just about every aspects of Japan through my experience living here. Feel free to leave any comments or just click the "clap" button if you like it.