simple use case

I'm looking for a simple use case -- or test data conversions, to help define the base transformer objects:
- types like dates, numbers, addresses, phone-numbers
- codecs for various representations of those types (unixtime, iso date, us street address, dotted/parens phones)
- conversions of one dataset into another. like gps samples -> topoJSON line or something.

If people have concrete suggestions, ideally with some sample data, would be great to post some.