The "free" in freely improvised music bedevils just about everyone. First-time listeners get shocked by the defiant absence of a songlike structure; musicians from outside the scene mistakenly think that "free" amounts to crazed, random sounds; and the performers, who, while reveling in freedom, listen and grapple with what to play next—maybe some serrated notes, a cantillating melody, or silence.

"Hokum" is what George Lewis, the improvising trombonist and author of A Power Stronger Than Itself, once called the ideology of unfettered, eagle-hearted freedom in improvised music. It doesn't exist, except as a futile goal. Every musician's sense of freedom must emerge within the performance itself, as the continual accumulation of melody, harmony, rhythm, timbre, tempo, and structure exerts a gravitational pull toward old habits, familiar licks, and other people's music. Taste, memory, technique, and courage (or lack thereof) are inexorably present. The oft-touted "sound of surprise" heard in the best improvised music is well nigh miraculous.

Hard work, not miracles, accounts for the persistence of the Seattle Improvised Music Festival. Curated and organized by musicians, North America's longest-running festival devoted to such adventurous music-making has endured since 1985. The first weekend (Fri–Sat Feb 13–14, Chapel Performance Space, 7 pm, $10/$15 and Sun Feb 15, Gallery 1412, 7 pm) boasts local favorites such as pianist Gust Burns and combustible alto-sax firebrand Wally Shoup along with a slew of notable players from across the country. Keep your ears open for Greg Kelley, a Boston-based trumpeter who wrests delicate tones and chirruping cries from his instrument, and the fragmented guitar-based electronics of Doug Theriault. Both perform solo and in mix 'n' match ensembles with violinist Mara Sedlins, "junk percussionist" (and Seattle expat) Andrew Drury, Burns, and others.

Next weekend features the astounding Lê Quan Ninh, a percussionist who will dazzle you with an astonishing, almost orchestral fusion of rhythm and timbre. And if you missed Cipher at the Is That Jazz? festival, you can catch one of Cipher's violinists, Tari Nelson-Zagar, as she performs in a trio with Drury. For a full schedule, see seattleimprovisedmusic.com.

Valentine's Day–minded lovebirds should flock to Joey Jewell's re-creation of the legendary Sinatra at the Sands album (Sat Feb 14, Triple Door, 6 and 8:30 pm, $70/$50, all ages). The Sinatra tribute singer and Jim Kerl's Swing Session big band swing nice 'n' easy through "Come Fly with Me" and "Fly Me to the Moon" and the rest, all in the original arrangements by the man Sinatra nicknamed "Q," Quincy Jones. Prices include dinner and drinks (I initially mistyped "drunks"—in the spirit of Rat Pack–era Las Vegas, those might be there, too). Reservations recommended. Also, the Esoterics, a splendid a cappella ensemble, sing a love-themed program (Sat Feb 14, St. Joseph's Church, 8 pm and Sun Feb 15, Holy Rosary Church, 3 pm, $15/$18) with works by Dutch composer Ton de Leeuw, Martha Sullivan, and Daniel Lesur's setting of the Bible's best (and erotic) book, the Song of Songs.