Feeling a little extra pep in your step today, rock fans? There's a reason, and it isn't just because it's Friday. It's also November 11, 2011 -- otherwise known as 11/11/11, or National Metal Day.

How did this happen? If you're any kind of rock 'n' roller, you shouldn't even have to ask, but in case you've somehow never gotten around to watching Rob Reiner's cult classic 1984 mockumentary 'This Is Spinal Tap,' we'll explain: it all stems from a scene in the movie when guitarist Nigel Tufnel (played with droll precision by Christopher Guest) explains that he has a special amp that goes past 10, all the way to 11. When asked if he couldn't just make 10 louder, Tufnel responds -- quite reasonably, we'd say -- "but these go to 11."

Since that moment, "going to 11" has become synonymous with rocking harder than anyone else around you, and we obviously couldn't be happier about today's national celebration of that spirit. In honor of Metal Day, the digital edition of 'Spinal Tap' is on sale for $4.99 today through Monday, and if you're on Twitter, the #GoTo11 hashtag is currently making the rounds.

But the fun doesn't end there. The folks at NPR, of all places, have put together a playlist for the occasion, appropriately titled 'These Go to 11: Songs Best Heard Extra-Loud.' It's an eclectic batch, featuring tunes from Kelly Clarkson, the Modern Lovers, LCD Soundsystem, and (of course) the Ramones. Meanwhile, Billboard has compiled a list of 11 Loud Moments in Music, including the loudest song shorter than two seconds ('You Suffer,' by Napalm Death) and the loudest rapper alive (DMX).

For our part, we've published a special list featuring the 11 Classic Rock Artists That Shaped Heavy Metal, and our brother metal site LoudWire has a whole bunch of fun stuff going on for this fake holiday.

So get out there and rock extra hard this November 11, dear readers -- and hit the comments to let us know how you plan on celebrating this once-in-a-lifetime occasion!

Watch the Famous "These Go to 11" Scene

You Think You Know Spinal Tap?