Devotchka

DeVotchKa (and all variants of capitalization thereof) is a quartet, hailing from the music mecca of Denver, Colorado. They originally were a backing band for burlesque models, including Dita Von Teese, before they released a few albums of Slavic-influenced mariachi folk gypsy indie rock.

Their song "How it Ends" has been used in many a commercial and trailer, including those for Gears of War and Everything Is Illuminated. Anyone who has seen Little Miss Sunshine will recognize some of their music upon hearing it. Despite this, they remain relatively underground.

They have added touring members, but the core of the band band is composed of:

Nick Urata (lead vocals, guitar, bouzouki, trumpet, piano, theremin)
Jeanie Schroder (sousaphone, upright bass)
Tom Hagerman (accordion, viola, piano, Melodica)
Shawn King (drums, percussion, trumpet, accordion, organ)

Lots of instrument switching ensues during live shows.

Devotchka provides examples of the following tropes:

Anti-Love Song: "You Love Me."
Break Up Song: "Such A Lovely Thing," "The Clockwise Witness"
Concept Album: Word of God confirms "How It Ends" is about a young Ranchero who goes off to war to find that his childhood sweetheart has married another man for his money.
Cover Version: Siouxsie and the Banshees's "The Last Beat of My Heart," Frank Sinatra's "Somethin' Stupid," The Velvet Underground's "Venus in Furs."
Epic Rocking: "Such a Lovely Thing," "The Enemy Guns," "The Man from San Sebastian," "Life is Short," "Dark Eyes."
Epic Riff: "The Enemy Guns."
Indecipherable Lyrics
I Need a Freaking Drink: Nick Urata's constant onstage companion: a bottle of red wine. He has been known to splash the audience.
I Will Wait for You: "The Enemy Guns," "You Love Me," "I Cried Like a Silly Boy."
Neoclassical Punk Zydeco Rockabilly: They have theremins, they have bouzoukis, they have an accordion, they have a sousaphone covered with Christmas lights on stage. What else do you expect?
Obligatory Bondage Song
Shout-Out: Their name is a reference to A Clockwork Orange. "Charlotte Mittnacht (The Fabulous Destiny Of...)" sounds like it's straight off the soundtrack to Amelie (Translated: The Fabulous Destiny of Amelie Poulain)
Silly Love Songs: So many that the band has heard tales of people meeting at their shows and later getting engaged or married.
Signature Song: "How it Ends."