In a genre all their own, tf3 will join the Heartland Festival Orchestra for some "Virtuoso Fiddlin' " March 16. "Over the years I've had some fantastic internationally-known soloists join us, but rarely have I found anybody that generates more sheer excitement," said David Commanday, artistic director and conductor of the Heartland Festival Orchestra. Short for "Time For Three," tf3 is the brainchild of three classically-trained musicians who met while studying at the Curtis Institute of Music in Philadelphia.