The theater was absolutely jam-packed for Sunday afternoon’s Chamber II outing — and the crowd definitely got its collective money’s worth, with four distinctly different works on the menu. In the course of his introduction, Director/host Geoff Nuttall apologized to the crowd for appearing in a suit-jacket that was missing a button, but he blamed it on his wife, violinist Livia Sohn, who had sat on his lap during the musicians’ preceding lunch break, and ZING went the button. Fair warning, Geoff: appear before us unbuttoned again, and we’re gonna have to report you to the fashion police. BTW, Geoff also revealed to us that he and Livia are now expecting their second child … congrats!

Kicking things off was composer-in-residence Osvaldo Golijov’s ZZ’s Dream, the same “butterfly music” that I’d heard just the day before at Music in Time. But this version — for piano solo — was distinctly different from MIT’s chamber orchestra scoring. As Geoff described it, the dreamy music is built on a foundation of “harmonic quicksand” — an effective metaphor. Pedja Muzijevic, a most versatile pianist (and harpsichordist), delivered it to beguiling effect.

This year’s Chamber offerings are two “mini-festivals” devoted to some of the finest music by Schubert and Mozart — and the Mozart part began in this program with his delightful F major “Oboe Quartet,” a tour-de-force that stands as one of the finest works ever written for the oboe. There to enchant us with it was the young oboe virtuoso James Smith, who was joined for the performance by violist supreme Carolyn Blackwell. The two of them are this year’s Chamber series “newbies,” in keeping with Spoleto’s long-standing tradition of bringing emerging artists to perform for us. The remaining players were crack violinist Mark Fewer, plus Alisa Weilerstein, perhaps the finest female cellist performing today. Despite a brief stumble in the first movement, our players delivered the piece to charming and graceful effect.

Then it was on to the program’s novelty, a work known as Oi Kuu (for the moon), by Kaija Saariaho. In fact, it was the festival’s first work (of quite a few) by Saariaho: Émilie, her opera, began its festival run last night — and there’ll be an MIT program devoted to her music on June 9. Scored for the unlikely combination of bass clarinet (Todd Palmer) and cello (Chris Costanza), this duet actually sounded in places more like a quasi-quartet. That’s because the cello part involves many double-note chords (and lots of unusual effects you wouldn’t expect from a cello); also, Palmer employed a phenomenon called “multi-phonics,” in which Palmer coaxed eerie-sounding overtones over his instrument’s foundation notes. This tranquil piece was more a work of texture and effect than of melody, and I thought it was pretty special. But not everybody agreed with me, as I overheard an elderly Charleston matron grumbling about it on my way out of the theater afterwards. Par for the course.

The concert’s grand finale was another tour-de-force, but this time by Russian Master Dmitri Shostakovich: his imposing, five-movement Piano Quintet in G minor. Shostakovich is best known for his glorious symphonies, but he also produced piles of wonderful chamber music — and this is one of his finest examples. Like most composers, he idolized baroque master J. S. Bach, and his devotion is heard in this quintet’s second movement, in the form of a wondrous slow fugue: my favorite part. I also got off on the marked contrast between the wild and raucous scherzo and the sunny, folk-toned final movement. Bringing this masterpiece to vibrant life were the members of the fabulous St. Lawrence String Quartet and mega-pianist Anne-Marie McDermott.

Great program, Geoff — you’ve done it again. But remember what I said about the button issue — and you better believe I’ll be watching.