Brian Lebarton, on November 24 2005, titled a blog post on his myspace page, "Twas a wondrous week of Yanni and Cannibal Corpse." It seems likely to me that this was what he had been recording! (This or the extremely similar "Premonition
" at least.) As that description accurately indicates, the song is a piano-based instrumental with violent spazzy outbursts. I guess the Alternating Piano->Noise Nonsense Instrumental is a genre Beck wants to master. Mission accomplished!
Brian later confirmed that "Acropolis Now" was recorded during the Nacho Libre
soundtrack sessions. The song was written by Beck, but he hardly appears on the recording (only as one of the shouters).
This was put up on beck.com as an exclusive track in July 2006.