Cities of Sand - Inception and Neil Gaiman’s Sandman series mash-up (Would this be a mash-up or a crossover?)

Seriously, if you know about Neil Gaiman’s Sandman series and haven’t read it yet, then you are willfully, knowingly, and purposefully depriving yourself of the single greatest artistic expression in the graphic novel medium of all time, and I have no sympathy for you. I am not exaggerating for comedic effect; I am absolutely dead serious about this.

And now you know about it. Make it the next thing you read.