I made this piece a while ago in the GIMP, using a quite interesting filter called flame. It has all sorts of weird patters that you can choose from, and then you can edit them further from there by mixing, matching, and randomizing. Cool stuff, but anyway, I eventually tweaked my flame to look like some smoke, and then I figured that I could make my smoke appear in the form of some sort of logo, so I just chose the Nike Swoosh, because it was the first one I thought of. This is a 1920 x 1200 wallpaper, so you can use it on anything.
On a separate and unrelated note, I saw the hangover today with some friends, and it was the most hilarious movie that we had seen in a very long time. Just great, great stuff, constant laughs… I strongly recommend it to anybody who loves a good comedy.