Even though the most recent post on this thread seems to be a couple years old, I feel obliged to add to it's history.
Sierpinski is a last name, but it's not mine. Wacław Sierpiński
was a Polish Mathematician, famous for his Sierpinski Triangle
(or called a gasket in 3D). I first found out about this in a book on Fractals and Chaos that I found utterly fascinating. It's a relatively uncommon name in modern society, so seemed to fit well as an internet moniker.
In other realms, my original handle was Kane, which was the name of a character that was portrayed in the Eye of the Beholder
video game manual. I currently use that handle (and picture) on other realms, but unfortunately it's quite common, so I tend not to use it as much where unique names are required.