I have long been aware of the Icelandic band Sigur Rós, known for slow post-rock ballads full of sadness and all, as displayed in the cover of their first internationally released album.
So it came as a bit of a shock when I stumbled upon a more recent album claiming to be from the same guys, with a bunch of naked guys running around in the countryside on the cover, and titled "With the sun in our hearts we play endlessly". Far from dark introspection, that title could even be a good motto for Parkour. And the music is, well, unexpected. A mixture of the original melodic ballads of the past with loud explosions of joy and an overall happiness difficult to ignore. It's even gotten to the point that the main singer, Jónsi, released an even-more-so-happy solo album to avoid tarnishing the band's former gloom aura! So definitely worth checking, and you can sample a lot of their songs for free on their website, as these gentlemen are decidedly very nice.