You can even make it a lot simpler by using a + sign in the email adress like eryxon+1@gmail, eryxon+2@gmail, eryxon+3@gmail, and google automatically ignores everything behind the + and sends everything to eryxon@gmail
edit: Maybe I was a bit unclear, but everything after the + is ignored, so this leaves you with infinite combinations, like when I had to make a US account for iTunes, i just used eryxon+US@gmail so your imagination is the limit here