One of the more memorable anime that I came across was "Mawaru Penguindrum"（輪るピングドラム）. It was an epic mindbending late-night anime which spanned 24 episodes from July to December 2011, but which I managed to run through within a few weeks. It could veer wildly from wacky comedy to very dark suspense, although the latter began to dominate in the last half of the series. But one of the regular sequences from episode to episode was the henshin sequence in which the keystone of the show, the young and innocent Himari Takakura transformed into the snarly dominatrix, the Princess of the Crystal. The sequence was accompanied by this frenetic tune by the in-series aidoru unit, Triple-H, which had included Himari as a member. And it went like this:
Yep, the above was one of the more bizarre versions of the sequence. In any case, what struck me about the tune was that these girls were screaming in their high-pitched voices: "ROCK OVER JAPAN!"...with all the linguistic hangups involved. The song may have been aidoru, it may have been techno, but rock....?
Then, my friend informed me that a few of the songs that come on the show were actually covers of songs performed by a 70s/80s rock band by the name of ARB, which was originally a short form of Alexander's Ragtime Band (yep, just like the century-old jazz ditty) before it became the official name. Another surprising fact was that the lead vocalist was Ryo Ishibashi（石橋凌）, now and for a long time an actor in a number of gritty crime movies and the star of the horror-thriller, "Audition" directed by Takashi Miike（三池崇史）in 1999.
One of the other songs covered on "Mawaru Penguindrum" was "Hai-iro no Suiyoubi"(Ash Wednesday....it's actually been translated as "Gray Wednesday", but seeing that today is indeed Ash Wednesday in the Catholic Church, I think a little leeway is OK). This was a track on ARB's 9th album from November 1986, "One and Only Dreams". The creation of the song was also at the hands of Ishibashi and Shirahama, and the lyrics try to push a discouraged man out of his funk...to a time before Blue Monday had arrived, let alone Ash Wednesday. The words may come across as pensive and introspective but the beat keeps an urgent pace. According to J-Wiki, ARB's efforts were an inspiration to later bands and singers such as Masaharu Fukuyama, Unicorn, Jun Sky Walkers and Hiroto Koumoto from The Blue Hearts. But I also think Ishibashi's voice has more than a passing resemblance to that of the charismatic Koshi Inaba（稲葉浩志） from B'z.
Triple-H (voice actresses Miho Arakawa, Yui Watanabe and Marie Miyake as Himari, Hibari and Hikari respectively) covers "Hai-iro no Suiyoubi" as a straight piano ballad with all of the sadness inferred. Considering how much of an existential hole the main characters of the anime were falling into, I think this version was quite appropriate. It popped up here and there throughout the series and was used as the ending theme for at least three of the episodes.
I have to say that "Mawaru Penguindrum" is probably the only anime that I've encountered that dealt with psychological horror, child abandonment, sexual abuse and subversion, Takarazuka set pieces.....with cute penguins....and probably other angles I have yet to discover.