The activity presented here is about an approximate or order-of-magnitude approach to information technology on the nano level, dealing in particular with the genetic code. Based on "There's Plenty of Room at the Bottom", the famous and visionary paper by Richard Feynman, the activity provides insight into a core concept of nanoscience and technology (NST): "information" and the extremely high information density in human DNA as a natural example of a nanostructure. Specifically, students calculate several estimates from Feynman's paper, using elementary knowledge about the chemical structure of DNA and basic mathematics. The activity is appropriate for upper high-school and early undergraduate students and nonmajor courses.