Collaborative night from Crows, friends

Dubbed “The Saturday Night Rebel Rockers Traveling Circus & Medicine Show,’’ the exuberant 3-hour-and-15-minute performance at the Bank of America Pavilion Monday night eschewed the standard opening act/headliner/hits/one-mood format. Instead, Counting Crows invited Michael Franti and Spearhead and Augustana to mix and match and rotate on their respective originals as well as a heap of fun covers throughout the night, in what felt like a heady mash-up of a vaudeville variety show, ’60s-style revue, reggae sunsplash, and an all-star benefit concert.

Van Morrison’s “Caravan’’ proved an apt opener and concert mission statement as Crows lead singer Adam Duritz, Franti, and Augustana frontman Dan Layus traded verses with ease, as they would repeatedly through the night. It was one of several times when all 19 members of all three bands plus special guest, actress-singer Emmy Rossum, were onstage at once. A contagious joy flowed from the stage when that happened, whether it was Spearhead’s pan-global booty shaker “Hello Bonjour,’’ a rambunctious version of Simon and Garfunkel’s “Cecilia,’’ or the equally apt finale, the Beatles’ “With a Little Help From My Friends’’ interpolated into the Crows’ own “Rain King.’’

The players, who played every song as if it was the last song, were either incredibly well-rehearsed or astonishingly keyed in to one another, as seemingly improvisational interludes were marked by perfectly timed harmony phrases and crisp musical stops and starts.

It was a canny move on the Crows’ part that paid off in spades for both them - showing them to be good and adventurous spirits - and their touring partners. Not only did it keep the night fresh and unpredictable, because you really never did know when one or more members of the main attraction would drop into a set, but it forced the audience to listen to the other bands in a new way.

Each band did get its own spotlight, and hits did get played - including the Crows’ “Mr. Jones’’ and Augustana’s “Boston’’ - but the collaborative spirit gave songs vintage and contemporary an exciting one-night-only spin.

Sarah Rodman can be reached at srodman@globe.com.