First get your top 20 artists and find out how many listeners they each have.
HANA Wakusei Music - 21
Värttinä - 42,099
下村陽子 - 119,536
ALI PROJECT - 49,268
菅野よう子 - 236,704
Thomas Dolby - 208,172
茶太 - 9,546
新居昭乃 - 39,236
Gorillaz - 2,598,315
Sanagi - 2,142
Modest Mouse - 1,808,178
Swing Out Sister - 96,433
Andreas Vollenweider - 137,964
Yo Gabba Gabba! - 13,028
Tomohito Nishiura - 4,317
Gnarls Barkley - 1,162,215
kukui - 8,739
Eiya - 55
志方あきこ - 38,394
佐藤天平 - 29,031

Then add them together: 6,600,393

Then divide by 20: 330019.7

Then divide by…

Take your top 50 artists. For each of these artists, collect the top 20 similar artists (where the artist itself is the #1 most similar). The resulting number of unique artists is your super-eclectic score. You can compute your own score at http://anthony.liekens.net/pub/scripts/last.fm/supereclectic.php

My super-eclectic score is currently

801/1000

The most similar artists for my profile are 桜庭統 (9), 伊藤賢治 (7), 浜渦正志 (7), 岩垂徳行 (7), Masaharu Iwata (7), 下村陽子 (7), 崎元仁 (6), 光田康典 (6), Rei Kondoh (5), すぎやまこういち (5)

1. How did you get into 31? (伊藤賢治)
Mana series and Romancing Saga, I believe.

2. What was the first song you ever heard by 22? (MintJam)
The oldest song of theirs on my iTunes is Rival, so I'm going with that. Sounds about right anyway.

3. What's your favorite lyric by 29?
It's between KOKIA and Lily Allen… Favorite by KOKIA is perhaps the "Mama, pinku no zou-san dayo!" in ピンクの象. Favorite from Lily Allen, in Friday Night, the line that goes something like "Nice dancing, love, but you should've worn…

First get your top 20 artists and find out how many listeners they each have.
HANA Wakusei Music - 9
ALI PROJECT - 17,806
茶太 - 2,141
Clouds - 5,614
下村陽子 - 38,102
Sanagi - 815
Modest Mouse - 763,763
Andreas Vollenweider - 33,480
Eiya - 22
kukui - 2,868
Thomas Dolby - 54,163
菅野よう子 - 124,574
葉月ゆら - 398
MintJam - 1,572
Gnarls Barkley - 483,397
上田雅美 - 4,936
Mika Matsuura - 297
Lily Allen - 368,878
OLIVIA - 32,597
Kaori Tsutsui - 21

Then add them together: 1,935,446

Then divide by 20: 96772.3

Then divide by the number…

English (24)
Sanagi – Manic Mind
Sanagi – Honey
Sanagi – A childish Cry for help?
Sanagi – Porcupine
Sanagi – Pippi
Sanagi - Dwarfs
Sanagi - Bang Bang
Sanagi - Lunatic
Sanagi - rabbithole
Sanagi – Sailor, me!
Clouds – 3 Minutes
Clouds - Say It
Clouds - Soul Eater
Clouds - Wave
Clouds - Immorta
Clouds - Blade
Clouds - Domino
Modest Mouse – We've Got Everything
Modest Mouse – Parting of the Sensory
Modest Mouse - Dashboard
Gnarls Barkley - Feng Shui
Lily Allen – Everythings Just Wonderful
Lily Allen - Friday Night
Muse - Supermassive Black…

Instrumental (20)
HANA Wakusei Music
下村陽子
Andreas Vollenweider
Eiya
MantJam
菅野よう子
Masami Ueda
Mika Matsuura
Hiroshi Ebihara
Kaori Tsutsui
Iain Ballamy
Hiroshi Yamaguchi
Little Wing
伊藤賢治
OSTER Project
増田俊郎
Rei Kondoh
in cremonica mono+
Ｍusical jarβ
Essence

Japanese (16)
ALI PROJECT
茶太
葉月ゆら
kukui
MintJam
OLIVIA
Chroma Chrome
KOKIA
hicalculator
妖精帝國
Chata@Yoko Shimomura
Do As Infinity
encounter+
Kihi-kihi
夜姫と熊猫
mimei

English (13)
Clouds
Sanagi
Modest Mouse
Thomas Dolby
Gnarls Barkley
Lily Allen
OLIVIA
The Cardigans
Gym Class Heroes
Gorillaz
Kings of Convenience
Linkin Park
Raining Jane

Various (1)
下村陽子

Finnish (1)
Värttinä

German (1)
Dschinghis Khan

Final Weight
Instrumental -…

Japan (26)
Eiya – 石と水と魔法と鉄の街
葉月ゆら – 5th album demo
HANA Wakusei Music – Huge Machine Fortress
茶太 – ムネノイタミ
Eiya – 翔
KOKIA - tomoni
松本梨香 – Spurt!
ALI PROJECT - CYBER DEVILS
ALI PROJECT – La caleche ～春の雪
モカ – かけひき
HANA Wakusei Music – 怪鳥の爪
HANA Wakusei Music – 愛は無敵
AAA – 最強Babe
Chroma Chrome – 明けない森
葉月ゆら – 「Ｃｈａｎｔ」＆「Apra la giuntura 〜綻
Mika Matsuura – The Emperor of Eternal Darkness
茶太 – バランス
HANA Wakusei Music – 魔性の指輪
hicalculator - Life is Game
ALI PROJECT – 共月亭で逢いましょう
wa. – Lapis lazuli
ALI PROJECT – ナルシス・ノワール
ALI…

Japan (33)
HANA Wakusei Music
ALI PROJECT
茶太
下村陽子
Eiya
葉月ゆら
kukui
MintJam
菅野よう子
Masami Ueda
Mika Matsuura
Hiroshi Ebihara
OLIVIA
Kaori Tsutsui
Hiroshi Yamaguchi
Chroma Chrome
Little Wing
KOKIA
伊藤賢治
hicalculator
妖精帝國
Chata@Yoko Shimomura
OSTER project
増田俊郎
Rei Kondoh
in cremonica mono+
Ｍusical jarβ
Do As Infinity
桜庭統
encounter+
Kihi-kihi
夜姫と熊猫
mimei

USA (5)
Modest Mouse
Gnarls Barkley
Gym Class Heroes
Linkin Park
Raining Jane

UK (4)
Thomas Dolby
Lily Allen
Iain Ballamy
Gorillaz

Germany (2)
Sanagi
Dschinghis Khan

Australia (1)
Clouds

Switzerland (1)
Andreas Vollenweider

Sweden (1)
The Cardigans

Finland (1)
Värttinä

Norway (1)
Kings of Convenience

Austria…

English (20)
Sanagi – Manic Mind
Sanagi – Porcupine
Sanagi – A childish Cry for help?
Sanagi – Pippi
Sanagi – Honey
Modest Mouse – We've Got Everything
Sanagi – Dwarfs
Lily Allen – Everythings Just Wonderful
Sanagi – Bang Bang
Modest Mouse – Parting of the Sensory
Sanagi – Lunatic
Clouds – 3 Minutes
Modest Mouse – Dashboard
Muse – Supermassive Black Hole
Gnarls Barkley – Feng Shui
Lily Allen – Friday Night
Sanagi – rabbithole
Clouds – Soul Eater
Clouds - Say It
Clouds – Domino

Instrumental (16)
Eiya – 石と水と魔法と鉄の街
葉月ゆら – 5th album demo
HANA Wakusei…

(This listing is by the artist's primary lyric language, if any. Some may be listed twice.)

Instrumental (20)
HANA Wakusei Music
下村陽子
Andreas Vollenweider
Eiya
MintJam
Hiroshi Ebihara
菅野よう子
Mika Matsuura
Hiroshi Yamaguchi
Kaori Tsutsui
Little Wing
OSTER Project
増田俊郎
Rei Kondoh
Ｍusical jarβ
伊藤賢治
in cremonica mono+
桜庭統
Essence
Rin'

Japanese (17)
ALI PROJECT
茶太
葉月ゆら
MintJam
Olivia
Chroma Chrome
KOKIA
hicalculator
妖精帝國
Chata@Yoko Shimomura
Ｍusical jarβ
Do As Infinity
encounter+
夜姫と熊猫
Kihi-kihi
松本梨香
Rin'

English (12)
Clouds
Sanagi
Modest Mouse
Thomas Dolby
Gnarls Barkley
Olivia
The Cardigans
Gorillaz
Gym Class Heroes
Linkin Park
Raining Jane
Kings of Convenience…