One of the featured guests at DragonCon were the Mythbusters build team, Kari Byron, Grant Imahara, and Tori Belleci. After the reading by Peter Beagle, I went to the autograph area to get something signed by him. As it turned out, the Mythbuster's table was right by his.
After I bought The Last Unicorn and had it signed, I went over and bought Grant Imahara's book Kickin' Bot at the Mythbuster's table and had them sign it:
They had a short line of people waiting for them, so I didn't talk to them much, but their were very gratious (and didn't charge for autographs; apparently some people do). I have heard of people having an "electric charisma". Kari Byron has it. When she talks to you, you get the impression that what you're talking about is the most important thing of the world, and she finds it incredibly facinating. [For Kari Byron admirers/stalkers, in the Q&A she said that she was already married]