Break a leg

The idiom "break a leg" is commonly used to wish someone good luck, especially in the performing arts, such as before a stage performance or a theatrical production. The phrase is believed to have originated in the theater world, where it was considered bad luck to wish someone "good luck" before a performance. Instead, actors and performers would say "break a leg" as a way of wishing each other success. The phrase is now used more generally to wish someone good luck or success in any endeavor, not just in the performing arts.
The exact origin of the idiom is unclear, but there are several theories about its origin. One theory suggests that it may have originated in the theater world, where it was considered bad luck to wish someone "good luck" before a performance. Instead, performers would say "break a leg" as a way of expressing the opposite sentiment, hoping that the performer would have to take multiple bows at the end of the show, "breaking" the line of their leg as they did so.

Goodluck on your street performance, break a leg!