Not that I've done it yet, but you can choose a name if you make a contribution to the administrators of this bb. I think it's about $40 or more, and jon and gapertimmy will let you pick one for yourself. Plus you get the coo little hand jibe next to your avatar! And you get some other sheeeit, too. See the home page under "cc.com brought to you by" for more details.
Otherwise, you're stuck with the names that the mods have set up. Go to the FAQ link and click on "What are these titles about?" to see what you have to live for if you're gonna go cheap.
Why just today, with my 700th post, I went from a lowly and detestable "sprayprentice" to a less lowly, yet equally detestable "bumblygumby"! All without chippin' in sheeit! I really do need to set aside some bucks for you guys! When the kid gets outta diapers and formula, I'll be rich! Rich, I say!