My oldest son teaches violin and other stringed instrument classes. They had their summer recital last week and he was playing around after it taking audience requests. I challenged him to play the HALO theme.....
Hah...He'd do it. My wife and I are the "Baron and Baroness" of our local chapter of a medieval group. I had my son follow me around one of the big war events once playing music. He also serenaded people outside one of the port-o-potty stations late into the night during one of the party nights and earned the nickname the "Privy-fiddler"!
He's one of those that can just listen to something and start playing it on almost any stringed instrument. At 5 yrs old, with his first violin, he would watch TV and start playing commercial theme songs.
I've helped him with a couple other cosplay rigs, but not HALO. He's mostly into league of legends now, but does HALO when I prod him. His younger two brothers are the main HALO ones now......and one plays guitar, the other violin, as well. Between the three, I almost have a quartet to follow me around a con!