Barry_Woodward: What say you?
re: title "a" not "an"
No, it's not an RPG. And your initial usage of "an" is correct. When the proceeding word starts with a vowel sound, "an" is used instead of "a". You can usually tell if you're using it correctly when it rolls off the tongue.
RPG is pronounced "ar-pee-gee", so you would say "an ar-pee-gee", not "a ar-pee-gee", as that would sound stilted. Unless the rules changed when I wasn't looking, of course. This is what I was taught, and it seems to make absolute sense as far as I can tell.
Of course, RPG stands for "role-playing game", so if you spell it out as such, yeah, the "an" should be an "a", since saying it in that form starts with a consonant sound. If you said "an role-playing game" out loud, you'd better hope nobody who works as an English teacher is listening, or they'll start having convulsions. ;)