Muhammad Yunus, architect behind the Grameen Bank and winner of a Nobel Peace prize, showed up this week on The Simpsons. In an unusually socially conscious episode, Lisa Simpson and Nelson (the class bully), learn some valuable lessons about poverty, and micro-banking is explained succinctly by a goat that sounds suspiciously like Apu.

If the Grameen Bank doesn’t ring a bell, it’s a worldwide effort to distribute micro-loans to the poorest areas of the world. Those who join the bank rely on mutual accountability and trust. Bank members are given seed money for small businesses (no collateral needed) and in return, they’re part of the bank community that holds their members accountable for their promises.

Evidently the episode was pushed forward by Yeardley Smith, the voice of little Lisa. Smith saw Yunus on Oprah several years ago and has since become a staunch supporter of the Grameen Bank. She’s visited microfinance clients in Haiti (just before the earthquake) and more recently, traveled to Bangladesh with Yunus himself.

“I would say about Muhammad Yunus is that the man has endless passion,” said Smith in an interview with Public Radio International. “He’s amazing and he has a fantastic sense of humor.”

Check out his cameo below.