Found some good Air Force Call signs at this site:
http://www.f-16.net/callsigns-R.html
Here are a few examples just from the letter R (to include Romo):
Rectum
Lt. in JROTC, just graduated this year. Known school wide as an egotistical, know-it-all @$$ho1e, hence "Rectum." He also wrecked his first car, a '98 Ford Explorer in a "ran a red light" incident; also killed a bird that flew into his car while going 80 on the highway (it's still there, by the way) and resulted in a large dent in his hood. He's also an all around speeder, hence "Rectum" = "Wrecked 'em."
Revlon
My fellow pilots in my ANG unit have little to no imagination. Wouldn't guess I was the only female aviator would you
Romo
Our instructor is from Texas and a big Cowboys fan. One of the students, being a Washington Redskins fan, told the instructor to take his Cowboys hat off and gave him crap the whole time. To get back at him we gave the student "Romo" after of course Tony Romo the Dallas quarterback
Rain Man
One night in a drunken stupor he urinated on his passed out buddy.
Here is one from the O list - a good example of be careful of what you ask for.
Omelet
Dutch pilot wanted to be called bouncer cause he used to be one at a club in Holland. Bouncer in dutch ("Uitsmijter") also means grilled egg. The squadron decided Bouncer sounded too cool so called him omelet. Lesson learned: NEVER ask for your own callsign!