The Metropolis ran an article a little while back on female manga fans - "fujoshi" - that like "boys love" stories. Specifically, it was a feature on the all-female band Fundan Juku, which I had written about in my other blog months earlier. Anyway, they had a side bar on "Dansou" (Butler), and the like, cafes in Ikebukuro that cater to women. I'm running that list here in the hopes that someone will help add to it. I don't get to Ikebukuro often, so I don't know how complete it is, and there's so many places I haven't been to yet in Akihabara that I don't know when I'll visit any of these. To be honest, I haven't seen any of the below places so far.
One of the first danso cafes in Ikebukuro.
1-31-15 Higashi-Ikebukuro, Toshima-ku. Tel: 03-5957-7297. Open daily noon-9pm. All-male groups can enter from 2-6pm.
80 + 1
The name is slang for yaoi (8 reads “ya,” 0 reads “o” and 1 is “i”), Men are allowed only after 6pm.
3-9-13 Higashi-Ikebukuro, Toshima-ku. Tel: 03-3984-7551. Open daily 3-10pm.
Hosts lots of tie-in promotions for anime.
3F, 3-15-6 Soto-Kanda, Chiyoda-ku. Tel: 03-3252-2031. Open Tue-Fri 2-10pm, Sat-Sun 1-10pm, closed Mon. Nearest stn: Akihabara or Suehirocho.
Good Rock - Boys:Style -
Good Rock offers a wide range of alcoholic beverages.
2-19 Kanda-Sudacho, Chiyoda-ku. Tel: 03-3254-5300. Open daily 3-10pm. Nearest stn: Akihabara.
Just outside Akihabara:
Cafe B’s Prince
Dansou cafe that had at least one "little brother" event. They're apparently tied to the B’s Prince idol group.
5-6-4 Soto-Kanda, Chiyoda-ku. Tel: 03-6380-9540. Open 10am-10pm. Nearest stn: Suehirocho.
Not mentioned in the Metropolis article, probably because it didn't meet the author's preconceptions, is Butlers Cafe, which I found on wikipedia. This is a western-style butler cafe with gaijin staff, opened in 2006 by Yuki Hirohata. Check here for the map and address.