Am I the Only Native Midwesterner to Never Have Heard of This?!

I'm reading the "Single in the Suburbs" Blog on MSN and the author mentioned PawPaws...what the heck is a PawPaw? And I've never seen a PawPaw in my life. And FYI, I spent my entire childhood growing up in Indiana and never left til I went away for college. How could this escape me?! Lol...