Speaking of totalists, John Luther Adams turned 53 Monday; Mikel Rouse turned 49 today; Art Jarvinen turns 50 tomorrow (January 27). Had Mozart gotten a little more daring with his cross-rhythms, I might have noted his 250th as well. Those are the breaks.
Come to think of it, though, the party scene from Act I of Don Giovanni, with dances going in three meters at once, is quite audibly metametric. Consider him celebrated.