I use Jester, DarkJester, or Jester2k_USAF. I am in the AF and I joke around a lot so thats how i got it. You can also get names from movies, tv shoes, or just somethiing funny. Its not like you have to put it on your resume. Just use what you like and make it simple. Make sure you would answer to that name or a shortened version of that name. For instance I used to be RadioactiveNinja. I was either called Ninja or Radio. Now people just call me jester. Its like a second name. I have friends that call me that and its my call sign here in the military so just pick something that you like and that you would like being called. I for one would not like being called nun