I'm working on a fantasy novel, so I'd love to meet my mage (as long as he could still do magic). Of course, after what I've put him through during this story I think he'd rather plot my assassination than sit down for a cup of tea. Most of my characters are probably trying to figure out ways to hide my pens.
To flip this question a little, are there any characters you'd like your characters to meet? At the moment, the characters from my fantasy novel are visiting the Enterprise. It's been very interesting watching my mage try to explain to Mr. Spock et. al. that yes, magic really does work. This isn't something I'd write down, but it's been an interesting thought experiment to see how the characters I've come up with would react to other established characters in totally different situations.