It’s no easy task to make music that excites people because it sounds so new and original. Not only have the Fiery Furnaces succeeded in making exciting music, but it’s genuinely good music too, with the tendency to intertwine storytelling, addictive melodies and inventive instrumentation — synthesizers, toy pianos, distorted guitars, drum machines and chaotic percussion.

Their new disc, misleadingly-titled “EP,” is a compilation of B-sides originally recorded for their first two albums. With 10 songs stretching 41 minutes long, “EP” could very well be another band’s full album (or, for the musically literate, an LP). But for the epic Fiery Furnaces, it’s a playful and versatile mini album (their last record “Blueberry Boat” clocked in at about 80 minutes). Most tracks sound like full-fledged medleys, with spliced-together tempos and abrupt instrumental changes. Though some songs are overly sprawling, “EP” has all the creativity and unorthodox experimentation the Fiery Furnaces have come to be known and loved for.

A brother and sister musical combo, the band is Illinois-bred, Brooklyn-moved Matthew and Eleanor Friedberger, who only started making music together as the Fiery Furnaces in 2000. Since then, they have been well on their way to becoming prolific artists — their first album “Gallowsbird’s Bark,” was released in 2002; their wildly-acclaimed sophomore effort “Blueberry Boat” came out last year; and it has reported that they’ll be releasing two more albums this year. The duo spent most of 2004 touring with Ted Leo & the Pharmacists, Franz Ferdinand, and the Shins, developing a reputation for energetically wild live sets, and their Bob Dylan penchant for revamping their material for live performances.

“EP” follows the spirit of reinvention. Some songs are remixed versions of cuts from their previous records, though molded in a different light. The opener “Single Again,” with its thumping but exuberant synth, is a more expansive version than the cut that appeared on “Blueberry Boat.” But “Tropical Iceland” is a completely transfigured, and improved, track — catchier and more melodic, a whimsical head-bobbing tune with a wailing electric guitar and simple piano notes in the background.

The Fiery Furnaces have a knack for trying different genres on and looking great in them. Not known to be sentimental or emotional, on the nostalgic “Here Comes the Summer,” they display harmonious verses and endearing lyrics: “July the third we stayed up late, remember?/ And thought how long we’d have to wait, remember?/ It’ll be so long until it’s soon/ It’ll be so long until it’s June.”

The disc’s golden song has to be the sweet “Evergreen,” with a great buildup of Eleanor’s soft singing over sweeping piano. The song includes a piercing electric guitar, but ends with a trailing, Elliott Smith-like acoustic guitar. This is about as melodious as it gets, and probably as traditional-sounding as the Fiery Furnaces will stoop.

There’s more trouble when the Fiery Furnaces get caught up in experimentation. Most of the time, their creativity is what makes the band so fantastic, but with such a diverse mix of random tracks, there are inevitably going to be the bizarre questionable ones. The violent shifts within the songs make them completely original, but sometimes creates a fragmentation that lacks direction. “Cousin Chris” starts off with dark piano choruses and Matthew’s sharp vocals, but in the middle of the song (after a “one, two, three, four” countdown) it plunges into a folky acoustic guitar riff and a brass solo with an echoing effect added to the vocals. In this case, the gorgeousness of the band’s songwriting is overshadowed by their overtly schizophrenic aesthetic.

“Smelling Cigarettes” also starts out with precarious piano arpeggios, but henceforth navigates between Eleanor’s singing-talk over marching band drums and crooning over a tranquil organ. After adding a toy-sounding drum set and crashing cymbals to the song, it descends into an ambient interlude straight from Brian Eno. The song resembles the theatrical mood changes of a musical, condensed into five minutes and 30 seconds, but here the slyness of the transitions make everything work.

Between dizzying composition and ingenious pop melodies, traversing between the eccentric, excited, and soothing tracks, the “EP” is a marvel for its creative inspiration. Most valuably, it is the band’s most accessible release to date — the colossal songs of their two full length albums are even more excessive. But while the experience of listening to the Fiery Furnaces is a rollicking and fun one if you’re in the mood, it certainly takes time to appreciate their music, and “EP” is no exception. Their cunning resourcefulness is amazing, yet it’s hard to acclimate or grasp the sometimes rambling and meandering theatrical collage of music, seemingly imprecise and slightly steaming of pretension.

That said, “EP” is a solid collection of songs, thanks especially to “Evergreen” and “Cigarettes.” Even if the CD is missing the tightly-constructed story lines of “Gallowsbird’s Bark” or the overflowing creativity of “Blueberry Boat,” it serves as a great introduction to the band work so far. The tracks are novel — especially the crashingly manic 6-minute closer, “Sullivan’s Social Club” — but their value goes way beyond novelty.