I am in the Business Center of the Westin O'hare Hotel where the Star Trek Convention is taking place, and it has been phenomenal.
Everyone here is so friendly (in a couple cases, perhaps, too friendly), and I've already got a minor reputation as "the guy with the Superman tattoos". Everyone has loved drawings I've done, including the actors who've seen them so far.
My conversation with Johnathan Frakes was as follows-
JF: Is that a drawing?
Me: Yeah.
JF: Did you do that?
Me: Yup.
JF: (Holds drawing at arms length) That is Awesome!
Me: (speechless, but in my mind saying, "No, THAT is awesome" about his saying my work is awesome)

My conversation with Brent Spiner went like this-
BS: I don't remember when I made that face.
Me: That is your "Ooooh, Shit."
BS: Oh, shit. Yeah. (Turns to JF) Look at this. It looks like a photo.
Me: (Cloud 9!)

John DeLancie's reaction was not as grandiose as Frakes or Spiners, but priceless, non the less. He was concerned about his marker not working on the drawing very well.