Megan McCardle ('Jane Galt') ends a long post with the phrase Carpe Couch, 'seize the couch'. If she had put it completely in Latin, it would have been Carpe Lectum. Or perhaps Carpe Pulvinar, especially if those using the couch are gods.

Some Romans had a semicircular couch, rather like the booths in the corners of some modern restaurants, but arranged for lying rather than sitting. They called this kind of couch a sigma, after the Greek letter. This sounds confusing if you think of the standard modern sigma used for mathematical summations that looks like an M tipped over on its left side. In classical times, the Greek capital sigma still looked like a Roman capital C: the angular version is a Byzantine thing. I suppose the Romans called the semicircular couch a sigma rather than a ce (pronounced 'kay') because outside of an alphabetical context sigma is more obviously the name of a letter, not just a random syllable.

Coming soon: Why 'sigma' resembles 'stigma', 'magma', and 'smegma' -- the words, I mean, not the phenomena they describe. The words are in fact etymologically parallel formations.

How's that for extreme nerdularity?