The entire metal community is celebrating today (Nov. 11)  as National Metal Day and cranking their favorite tunes ... well, to 11. There's something about the date -- the synchronicity of numbers, the cutting parallel lines  -- that when 11/11/11 is written out that looks pretty metal. But the real metal-ness of National Metal Day dates back to the classic 1984 rock movie satire 'This is Spinal Tap.'

In one of the films best and most quoted scenes (watch below), guitarist Nigel Tufnel (Christopher Guest) is showing his gear to filmmaker Marty DiBergi (actual filmmaker Rob Reiner) and he points out that his Marshall amps don't go to "10," like most amplifiers, instead all of the dials go to "11."

When asked if the amps are louder than those used by other bands, the slightly dense Tufnel says "Well, it's one louder, isn't it?" Continuing the gag, DiBergi aks, "Why don't you make 10 louder, and make that be the top and make that a little louder," Tufnel pauses like a deer in headlights for a few moments, points to the amp and repeats, "These go to 11."

To celebrate the legendary film, Amazon.com, iTunes and X-Box are selling 'This is Spinal Tap' for $4.99 between now and Monday. In addition, VH1 Classics and PalladiaHD are airing the film throughout the week. In addition, today is also being dubbed Nigel Tufnel Day. You can keep track of the day's festivities on Twitter and Facebook at the hashtag #GoTo11.

For a "fake" metal band, Spinal Tap have done pretty well, releasing three albums -- the 1984 film soundtrack, 1992's 'Break Like the Wind' and 2009's 'Back From the Dead.' In addition, their songs have been included in the video games 'Guitar Hero 2,' 'Rock Band' and 'Rock Band 2.'

Watch the Memorable "These Go to 11" Clip From 'This Is Spinal Tap'