Some dude at the bus station wants to know what bitcoin is.
you don't have much time and he won't be able to take in to much information.
a simple look it up online won't do, because that's not interesting enough to read a lot of boring stuff online.

What are 2-3 short(!) key features of bitcoin, which i could tell him, so that he has a basic understanding what it is? And of course so he will be interested to learn more about it.