This yarn: (which, incidentally is gorgeous Gaia Organic wool dyed in the Cornucopia colorway by Over the Moon)

became these longies (wool pants used to cover a cloth diaper):

but alas, my little boy was born so huge that he didn't fit into them.  So I gritted my teeth, crossed my fingers, and frogged the yarn.  Then I crocheted up a pair of shorties, which work superbly as an overnight cover.

One the whole, I spent about five hours working with this yarn.  If I was to recommend a yarn to spend five hours with, it would definitely be this.