Let them give it a whack on your computer.
Let me never fall into the vulgar mistake of dreaming that I am persecuted whenever I am contradicted.
~Ralph Waldo Emerson
"I was just the one with the most unsolicited sombrero." - Traegus
Aett's got the best suggestion. Let them have a few hours making and playing characters. Answer questions but don't tell them what they need to do or backseat drive. Show them all sorts of awesome things in the game.
Perhaps even give them access to a high level character for a while on your account. Show them what a high level tanker can do!
Or take a level 30+ troller to AP and use Wormhole to send Mobs flying gracefully through the air, ragdolling on walls, trees, and railings. =-3
-Rachel-
Yeah, what Aett said. Let 'em play around with your characters some and then let them make one or two of their own and see just what the character creator has to offer. Then let 'em go back to looking exactly like everyone else in their other MMO.*
*Yes, it's hyperbole, but not by all that much in many cases.
Iscariot's Guide to the Tri-Form Warshade, version 2.1
I'm sorry that math > your paranoid delusions, but them's the breaks -- Nethergoat
P.E.R.C. Rep for Liberty server
Grab their computer while they're not looking, install the updater and game, and get a trial account open for them 
Please read my FEAR/Portal/HalfLife Fan Fiction!
Repurposed
I've been on COH/COV for over a year now, and I've only got 1 real life friend who plays with me. Everyone I ask either plays another MMORPG or they "don't have time". Any suggestions on how to get your real life friends to join up?