Collaboration fever is yielding some of the more unexpected artistic masterstrokes in Philadelphia these days.

A series of such collaborations came sliding together on Thursday, so that one could encounter eight of the city's most august institutions in four events sprinkled over morning, noon, and night.

Some of the odder pairings: At the Fabric Workshop and Museum, Pulitzer Prize-winning composer David Lang had three people whistling to a 4-billion-year-old rock that predates life on Earth. Noted Curtis Institute musicians wandered among listeners in Kimmel Center's dimly lit, subterranean SEI Innovation Studio playing the hypnotic minimalist chamber work and manifesto In C by Terry Riley. Later, Leonard Bernstein and George Gershwin were the Philadelphia Orchestra's treat after a day of migrating between museums and concert halls by trolley and bicycle, amid light snow.

First venue was the Philadelphia Museum of Art's Perelman Building, where nothing less than the creation of the world is being contemplated - as part of the conceptual art works in the new exhibit "Allora & Calzadilla: Intervals." The question for me is how much the music pulls its weight apart from its overall concept. A Concert for Elephants, a film about taxidermied animals with well-mannered chamber music played by Relache ensemble, did not.

In contrast, In the Midst of Things (Christopher Rountree's rejiggering of Haydn's Genesis-based oratorio The Creation) took the concept to a new level. Though sometimes asked to sing the deconstructed music running backward (word pronunciation and all), the Crossing choir allowed the music to unfold with distinctive poetry (as opposed to mash-up shards) while the singers moved deliberately through the atrium, backward and forward, together and in sections. Repeat performances are noon, 1, and 2 p.m. Dec. 13, Jan. 24, Feb. 21, and March 21.

Across town at the Fabric Workshop and Museum, the aforementioned 4-billion-year-old rock was suspended by a string in a bare white room with merciless fluorescent lights. There, three members of the Crossing performed Lang's 20-minute piece, titled Lifespan, written for the exhibition. It may be this adventurous composer's most curious piece, with little conventional vocalizing. Instead? Whistling and sounds alternately suggesting panting, the flapping of wings, and other natural phenomena, all based around simple melodic intervals.

The score consists of 30-second cells that are repeated, mostly polyphonically, as the trio's leader sees fit, with the singers all clustered around the rock as if breathing life into it. Much personal subtext from the singers, who were faced with animating this highly unorthodox music; afterward, they talked about contemplating the unfathomable age of the universe against the shortness of human life. The piece will be repeated 300 times, whether there are listeners or not, at 1, 2, and 3 p.m. nearly every day through the April 5 exhibition closing.

Lang is a clear descendant of Terry Riley's In C, first heard 50 years ago and consisting of 53 musical phrases that can be assembled by a variety of musicians with a certain amount of leeway, perfect for the club atmosphere of the Innovation Studio (in a coproduction with the Kimmel Center). Musicians included modern music specialists eighth blackbird, the Aizuri Quartet, and the Curtis 20/21 Ensemble, which maintained an effortless pulsating musical orbit with a variety of instrumental color that made the piece feel like some protoplasmic organism. Lang suggested the beginning of life; Riley depicted its process.

Upstairs at Verizon Hall, the big news was that Philadelphia Orchestra guest conductor Bramwell Tovey unveiled his own trumpet concerto, Songs of the Paradise Saloon, based on a raffish operatic scenario about a 19th-century con man, musically portrayed by Alison Balsom with three different horns, including a sweet-talking flügelhorn. Genre-wise, the piece is like Strauss' Don Quixote with its narrative emphasis and sense of personality contained in instrumental solo writing.

This major addition to the small trumpet repertoire made you all the more aware of how Gershwin carefully chose instruments to replace voices in his Catfish Row: Suite From Porgy and Bess, and how much Bernstein oddly failed to do the same in his Symphonic Dances from West Side Story. A semi-pops program, the concert was a chance to hear this emotionally generous music played at a high level that is rarely possible in the shortish pops concert rehearsals.

Additional performance: The Philadelphia Orchestra's program is repeated at 8 p.m. Saturday at the Kimmel Center. Information: 215-893-1999, www.philorch.org.