The Hot Summer Nights Music Festival presents Mostly Mozart at the Missouri Theatre in a program that features Mozart’s vocal and orchestral genius. “Symphony No. 40 in G Minor” showcases his instrumental brilliance while also portraying his lyrical soul. The Resident Opera Artists perform vocal arias across the composer’s spectrum, and MSO principals Staskevicius and O’Hara perform a virtuosic duo my Bottesini. $25 & $31.