Hmm...maybe toss out your stuff without specifying the gaming system?
(my advert was: "Adventurers Needed!
No experience necessary. Think you have the boldness,
cunning, and fortitude to slay monsters, fight evil,
and reap treasures in the doing? Contact 'One-thumb'
at The Black Dragon Inn for details -
http://www.earthlink.net/?????????? <-- where ???? was a webpage where
I simply described what an RPG
was and a general description of
my 'world' without mentioning C&C.
And, of course, my e-mail address
so folks could contact me.
Then, if folks show up with negative preconceptions/prejudices ("Oh, man! It's not
MY brand/version/edition"), simply ask them to play to find out if they actually might like it. I'd suggest having many types of pre-rolled characters ready to rock so they don't even have to make the effort of character generation, but can start playing immediately -- this'll (hopefully) short-circuit those who might object to such "wasted" time since C&C isn't their 'game-of-choice'.
If you've got everything laid out and ready to play, you can smilingly say, "C'mon, let's play...I'm ready. Isn't that what we're here for?"
Probably best to make sure that first game kicks off exciting and stays
intriguing, while being a good intro to using the SIEGE engine to do all
of what 3e & 4e do AND MORE. I think once a gamer realizes they can try
pretty much anything they can come up with in C&C, they'll be hooked
as I was.
Another possibility: create a group from newbies with little or no prior
preconceptions, and you all learn together. I find that describing
RPGs as 'street theatre in your living room' is a good way to help
folks get it.
Good luck.