Sponge here...
It's a variation on my last name. Two different clerks, within a short time span, mis-spelt my name on 'public' documents. Others in my group saw this and it kinda stuck.... It works well enough for me.
Oh...along A CHICK's lines:
"SPONGE" was already taken by some obscure entity in Ontario. Figure that what loser would want a license plate that says "SPONGE"!?! sheesh! So...I got mad and just chose a bunch of numbers and letters at random. I did however, manage to get "SPNGE" for my bike.
(-:
Sponge
p.s.
my real name is Eric