I had a Gmail account and my cousin wanted to make a YouTube account with this email. I was wearing a shirt that said Zig Zag. ZigZag didn't work, thezigzag didn't work, so we tried Thezigzagjunior and it worked. So it stuck for a while.
My friend on Skype was bored and renamed me MasterZigZag then it stuck, still with me. Wish I could change my MineCraft name though.