The Brian Irvine Ensemble isn't an orchestra, really. It's more of a traveling explosion -- a kinetic, freewheeling circus where the musicians dance, blow bubbles, cluck at one another like chickens, fall over "drunk" and watch imaginary notes float through the air, all while making some of the most exhilarating and imaginative music you'll ever hope to hear.

The force behind this engaging madness is Irvine himself, a free-spirited composer from Northern Ireland who brought his 12-man ensemble to the Library of Congress on Friday night. Irvine is a serious musician (he won the British Composer Award last year) but fortunately he hasn't let that cramp his style. His music draws on anything that crosses his ears -- free jazz, punk, the stately icons of the classical repertoire -- and reinvents it all with cheerful abandon. A Dixieland blues will morph into a firestorm of hard bop, then melt into a delicate Satie-esque piano melody while snatches of absurdist dialogue are passed back and forth among the musicians.

Anarchic? Not to these ears. The music is tightly written and superbly paced, and it moves like a piece of theater (which it largely is). Tedious clowning? Not at all. Irvine may leap around comically in his ill-fitting suit, conducting with fingers and elbows, and the musicians may be bursting out in smiles the entire time -- but it all comes across as musical play in the highest sense: exuberant, spontaneous and irresistibly alive.

Stephen Brookes