Finally got around to writing an article that was bowling around in my head.

Have three basic examples there, remembered a fourth (mapping table), so
go take a read, offer a comment and let me know if there are more
examples. I know there are, I just cannot think of it offhand.

List GCV
Structured GCV
Casting a nodeset as a string, get all the string bits smushed.
For-each over nodesets and how elements in argument builder are each a set.

One more would be mapping table. Store result in a nodeset, and if you
get back more than one returned value, you get a nodeset of all returned
values. VERY useful.