PorchFest is Somerville’s epic, annual, locally-grown, do-it-yourself, loosey-goosey, marathon hootenanny. Anyone can participate in the open-source music festival. And with about a million bands performing (okay, actually more than 175 bands; same difference) on their porches (thus the name) and in backyards across the city this Saturday, it seems like just about every musician in town does.

Inspired by an event in upstate New York, it exploded locally when the geniuses (really) of the Somerville Arts Council first copycatted it here in 2011. Flavors range from Americana to West African percussion to classical; from “endearingly awkward pop/rock” to “experimental post-industrial math-positive folk-punk”; from “one person, a hammered dulcimer and a few tunes” to some ladies promising to “lovingly give your ear holes some of the best dyke music you’ve ever heard.”

The May 17 shindig is like an open-studios day, spanning the whole city, but for music. It’s one more example of the creativity bursting at the seams of Somerville and its generous desire to share. And it’s all free.

Below are some bands you shouldn’t miss. (Full schedule here.) But first some tips. The schedule groups neighborhoods by time, so performances in east to Central are noon to 2 p.m., Central to Willow is 2 to 4 p.m., and west of Willow runs 4 to 6 p.m. Parking can be challenging, so walking and biking are recommended. And the since rain is currently forecast for Saturday, note that the rain date is the following day, Sunday, May 18.

Freezepop | 163 Summer St., Bradford Court | 2-4 p.m.

Epic synthpop music that will satisfy your ‘80s dream to boogie in a computer with Tron. Another point in their favor: They’ve been known to brandish two keytars at once.

Charnwood Porchpickers | 29a Charnwood Road | 2-4 p.m.

Goodtimes rootsy band. If they don’t have a jug to go with their guitars, mandolin and accordion, it’s gotta only be a matter of time.

Seana Carmody | 46 Bow St., "The Doll House" | 1-2 p.m.

You may remember her long ago from the Swirlies. These days, she’s manufacturing irresistible, lilting, dreamy pop tunes.

Second Line Social Aid and Pleasure Society Brass Band | 20 Lincoln Parkway| noon-2 p.m.

A big, raucous, funky New Orleans-style party band that rarely stands still. The folks who founded the amazing, annual Honk marching band fest.

Matt Glaser and friends | 18 Park Place | noon-2 p.m.

This fiddler has performed with stars from Bob Dylan to jazz legend Stephane Grappelli. You might also recognize Glaser, the artistic director of Berklee College of Music’s American Roots Music Program, from his appearance as one of the talking heads in Ken Burns’s TV documentary “Jazz.”

Poor Everybody | 11 Pearson Road | 2:30-3:45 p.m.

The band’s music ranges from barreling along rock and roll to a psychedelic Americana version of Jimmy Driftwood’s “Tennessee Stud.” With some ‘60s style organ. Request their great twinkling guitar and piano cover of the doo-wop classic “I Only Have Eyes for You.”

Opposite People | 19R Prospect Hill Ave. in the back | noon-2 p.m.

Big horn-driven afrobeat ensemble. And check out their location: walk past the house, down a driveway, to find the band playing in front of a hidden second house, in what is basically a cozy outdoor room.

Somerville Symphony Orkestar | 74 Walnut St. | noon-2 p.m.

As they describe themselves on Bandcamp: “Blossoming from the Slavic heart of Greater Boston, the Somerville Symphony Orkestar is an all-original Eastern European punk funk band.” Yes.

Sheboom | 43 Munroe St. | noon-2 p.m.

A deliciously loud gang of graying ladies who met in a four-week Brazilian drumming class taught by Marcus Santos in 2010. “We spotted fifty in the rearview mirror a while ago,” they say. “Among us are activists, artists, educators, moms, fundraisers and entrepreneurs. But drumming is what we really like to do.”

PowerSlut | 32 Stone Ave. | noon-2 p.m.

Wisecracking, potty-mouthed, “slut positive,” volume-cranked, indie rock with something of a ‘60s vibe and a lot of contemporary attitude. For example, their ditty “Catholic Boy”: “When I first laid eyes on you/It started off pretty well/Until you told me that if we banged/You would go to hell.”

Somerville Ukulele Club | 163 Summer St., apt 1 | 2-4 p.m.

Funny group of ukulele aficionados—augmented by the occasional kazoo and toy xylophone—who take a shine to old timey-ish tunes rife with double entendres and endearingly twee covers of recent pop hits like Carly Rae Jepsen’s, uh, classic “Call Me Maybe.”

Jon Bernhardt | 9 Charnwood Road | 2-4 p.m.

He promises: “Theremin versions of songs that are completely inappropriate for that instrument (mostly punk and new wave classics).”

Dirty Water Brass Band | Nave Gallery Annex, 53 Chester St. | 4-6 p.m.

Another one of Somerville’s hot marching bands, this gang is powered by their love for classic 1960s and ‘70s soul.

Dan Blakeslee | 83 Josephine Ave. | 2-4 p.m.

Foot-stomping, polished troubadour Americana from a youngish gent who gives the impression that he’s seen too much heartbreak and hard times while riding the rails during the Great Depression.

Big Blue World | 10 Packard Ave. | 4-6 p.m.

Request an encore of their sweet, delicate Americana cover of Paul Simon’s “I Know What I Know” from last year's PorchFest (above).

(Pictured at top: Members of Die Nacktschnecken and A Proper Mob peforming at the 2012 PorchFest. Catch them on Trull Street this weekend. Photo by Greg Cook.)