You can try religious bookstores. They often have collections of devotional stories, some of which might be humorous. Look for anthologies specifically labeled as having 'inspiring and funny' devotional stories.
Online religious forums can be a great place. People from all over share their own experiences, and among them are surely some short funny devotional stories. You can also check the websites of religious organizations. They sometimes post such stories to engage their members in a more light - hearted way about their faith.