Here's your hilarious joke:

At the 3rd grade violin rehearsal ... ... Donnie Corleone Jr. walks in, opens his violin case and unveils, to the shock of all, a tommy gun. The teachers are livid, panic nearly ensues, but Donnie just starts laughing uncontrollably. "What's wrong with you? This is serious! Why are you laughing?" "Because I just imagined dad holding up the bank with my violin."

"Abby Mathilde" Permalink