From an up-and-coming indie band struggling on the music-saturated streets of Los Angeles to an immensely successful international musical force, [lastfm link_type="artist_info"]Foster The People[/lastfm] are models  for many other small bands looking to reach mainstream success while maintaining their musical integrity and not selling out.

Less than a year ago, Foster the People played a free residency at a small bar in Los Angeles. Tonight, they played an amazing free streaming show at the iconic Ed Sullivan Theater for Live on Letterman.

Watch Foster the People’s Live on Letterman webcast right now on-demand:

[cbsvideo]http://www.cbs.com/late_night/liveonletterman/foster_the_people/video/?pid=0b9vUi6EQsmc07_kFXL3u7M_Kx2VlRZg[/cbsvideo]

@fosterthepeople my night schedule has been completely cleared for this event #LiveOnLetterman #NumberOnePriority – that's dedication yo —
Rachael Bane (@RaeNi_Studio) October 27, 2011

The first track that [lastfm link_type="artist_info"]Foster The People[/lastfm] played, “Houdini,” is an upbeat, synthy dance gem with soulful vocals and lyrics that entreaty the listener to “focus on their abilities,” despite apparent self-conscious doubts.

Foster The People went into their second track of their Live on Letterman set, “Miss You,” a lesser known tune from their debut album Torches.

Ripping through the raw, pounding drums, “Miss You” takes the focus away from the electro-buzz beat of many of their other songs, showcasing the rhythmic talent of Foster The People with a powerful instrumental ending and the sweet and stripped-down vulnerability Mark Foster‘s voice–without leaving him in puddle of sentimentality despite lovelorn lyrics like “I really miss you I miss you, I said smile at the chance just to see you again.”

OMG OMG OMG. ARE THEY REALLY PLAYING MISS YOU? I'M ABOUT TO CRY. #LIVEONLETTERMAN—
Romina Fuentes (@Rome_at_Home) October 27, 2011

After “Miss You,” Foster addressed the audience with his deceptively low voice and shy smile : “This stage has a lot of history…I can’t believe I’m standing on it. All I can think about is [lastfm link_type="artist_info"]Jim Morrison[/lastfm] being on acid performing “C’mon Baby Light My Fire.”

For their third song Foster The People lit the musical fires of the audience with  “Life On The Nickel,” a quirky experimental synth-pop tune with a tongue-in-cheek take on making money and living the dream–or not.

Foster sings lyrics he undoubtedly has first-hand experience with as an artist, “I’ve been right, I’ve been wrong/my smokes have come and gone/I’ve been crazy, been fed/enough to not wind up dead.” His take on the rat-race of life is a lot more pragmatic than the cheerful tinkle of the xylophone would indicate.

Totally having a dance party via Skype date to @fosterthepeople #liveonletterman Thanks tech-no-lawl-o-gee!—
Hanna Soltys (@HannaSoltys) October 27, 2011

Starting slowly and melodically, with a slight groove-funk bass in the background, Foster The People’s fourth song took a deep, shoegaze-y breath and refocused their energy on the introspective mid-tempo “I Would Do Anything for You.”

The song boast [lastfm link_type="artist_info"]Beach Boys[/lastfm]-esque melodies and love-fueled “ooo la las” that supplies an endearing emotionalism to an otherwise cool electro-pop ballad.

oh mark foster<3 you're so adorable. Foster the People Live on Letterman on CBS.com: soc.li/mVZ9RTk—
Mikayla Jade (@MjadeeP) October 27, 2011

One of their most popular “in-concert” tunes, “Call It What You Want” was Foster The People’s fifth tune of the night. With its expansive chorus, cymbal-clang steely dance beats, and surging piano riffs, “Call It What You Want” is an infectious ’80s-tinged tune that still maintains modernity.

Watching @fosterthepeople streaming #liveonletterman proves I really need to go to one of their concerts #sogood—
Amanda Marsh (@AmandaRae223) October 27, 2011

For their sixth song, Foster The People played their obviously Britpop inspired hit, “Don’t Stop.” The song has elements of late ’90s[lastfm link_type="artist_info"] Blur[/lastfm] and [lastfm link_type="artist_info"]Supergrass[/lastfm], cheeky whistles, Foster’s diffused tenor, and a sound effect we have lovingly deemed the Wizard of Oz witches laugh.

For their last two songs, Foster The People played their dance-driven, yet provocative synth-rock track “Helena Beat” and an extended version of the song that, arguably, made them as famous as they are: “Pumped Up Kicks.”

Trailing off, Foster let the audience at the New York’s Ed Sullivan Theater sing along before going into an exuberant dubstep remix of the song and shuffling wildly on stage while playing the upright kick drum and cowbell.

OMG this remix of Pumped Up Kicks!! #inheaven #LiveOnLetterman—
Toby Benson (@TotallyTobyy) October 27, 2011

Moments like this really show Foster The People for what they are: the sound of the future–a sound that perfectly fuses the immediate gratification of pop, the emotive strength of rock, and the infectious dance-floor swoon of electronica.