Was poking around on the Duolingo website, and I see they sell a couple of shirts with popular Spanish phrases from the Duolingo course. I think they should sell shirts with phrases from various languages; for the Esperanto course, the clear winner would be "Mi fartas bone, ĉar mi havas anason."1
I'll let you look that up in Google Translate. :-)
This is a real sentence from the course.