Back in my high school days when I was playing in rock bands, we would try to play Rush's Cygnus X-1, because it was nearly impossible to pull off. And it is probably for that reason that Rush didn't play it that often, either.
However, Rush pulled out all the stops on their final R40 tour, and they added this epic piece to their set list. But when the DVD was released sometime later, you couldn't appreciate the full spectacle of just how awesome the lights and lasers were during this instrumental.
The other day I happened to discover someone's cell phone recording from the back of the theater during the R40 show, and I combined it with the DVD's stage footage to create the following picture-in-picture video. (The picture-in-picture overlay kicks in around the 20-second mark.)
For all of the Rush fans out there - enjoy. For all of the non-Rush fans, it's okay - Geddy doesn't sing on this one.