The holiday season abounds with special events and performances, but few are as weird and beautiful as Tuba Christmas. These locally organized events take place all over the U.S. (and in some other countries as well). You sign up with the national organization, pay a nominal fee, and get the specially arranged music. Tuba and tuba-related instruments like the euphonium, baritone and sousaphone are mostly on the back benches of the orchestra. They rarely get the lovely melodies that go to higher-pitched instruments. At Tuba Christmas, they do it all. The events usually take place in public spaces where people can come upon it easily -- shopping malls are favored. For the listeners, a common response is awe at the warm, enveloping, resonant sound.