Upstate New York-based alt-rock ensemble Ra Ra Riot, founded in 2006, is comprised of Milo Bonacci (guitar), Alexandra Lawn (cello, vocals), Wesley Miles (keys, vocals), Gabriel Duquette (drums), Mathieu Santos (bass), and Rebecca Zeller (violin). The late John Pike (drums, vocals) co-wrote much of the group's 2007 debut release. Collaborations/shared stages include Chris Walla (Death Cab for Cutie), Rostam Batmanglij (Vampire Weekend), The Editors, and legendary New Wave unit Bow Wow Wow. With five releases to date, get "Winter '05," from Ra Ra Riot's 2008 project The Rhumb Line. 
Icelandic multi-instrumentalist/songwriter Ólöf Arnalds was born in the Reagan era. By the age of 8, she picked up the violin and classical singing and never put them down, studying music through grad school at the Iceland Academy of the Arts. After some finger-bleeding, Arnalds took off with indie-rock ensemble múm in 2003. Three years later, she recorded her solo debut with Kjartan Sveinsson (Sigur Rós) at the helm, earning Record of the Year in Iceland. Her sophomore set, also produced by Sveinsson, is set for release this year. Download "Náttsöngur," from Arnalds's Við og Við.
Beirut is the indie-rock ensemble founded in the mid-aughts by New Mexico import Zach Condon (multi-instrumentalist, songwriter). Musical chairs include Nicholas Petree (drummer), Perrin Cloutier (accordion), Jason Poranski (guitar, mandolin), Paul Collins of Soft Landing (guitar), Jon Natchez (baritone sax, clarinet, glockenspiel, ukulele, mandolin), Kristin Ferebee (violin), Kelly and Tracy Pratt of Arcade Fire (trumpet, flugelhorn), and Heather Trost of A Hawk and a Hacksaw (violin, viola). Shared stages/collaborations include Grizzly Bear, The New Pornographers, and The Jimenez Band. With a handful of releases to date, start with the deliciously old-timey "La Llorona," from 2009's March of the Zapotec. 
United Kingdom's Muchuu is brother and sister act Milky and George. Milky sings and writes the lyrics, and George writes the melodies, rocks the computer, sings backup, and plays the keys. After issuing a couple of singles, they just released their first full length. Get "When I Am Brave," from Muchuu's 2010 debut Adventure We Go. It's groovy and whimsy filled.
