Officer Bas Kol
Every day a bas kol, a heavenly voice, calls "shuvu banim shovavim, return to me o' wayward sons." [Chagigah 15]
Every day a bas kol. The trick is, you have to hear it.
Note to my friends in the peanut gallery: I know Chagigah tells us that the bas kol says: shuvu banim shovavim chutz me'achar, and I know this agadata isn't a kiruv agadata, but an anti-apostate agadata. So, sue me.
Hat tips: Sarah and Allison