Short yet interesting: in search of a sample

time to read 1 min | 81 words

One of the feedback points that I got about the book was that there need to be a fully working Boo program, before we start to introduce the DSL ones. The problem? I can't think of anything that will be both interesting and short enough to put into a book.

My limit is at about two pages, and I don't want a tedious example. Any suggestions?

One major point, it should have as little background assumptions as possible.