Loved the opening! I also like that fantasy is making more of a foothold into the geek/nerd verse in Big Bang. Loved all the jokes, but mostly the back and forth between Stewart and Leonard at the start and between him and Brent Spiner at the end. It's really reminiscent of all the cons I've been to and had to haggle to get good prices for cool stuff. I've always liked it when Leonard plays the straight man to Sheldon's funny and this episode seemed kinda like a throw-back to the early seasons in that way.
Howards' storyline was kinda annoying and this is something I don't like seeing again. Although, SPACE! It would be soo awesome to go to space, and I suppose part of the reason I didn't like the storyline was that I couldn't believe that Bernadette wouldn't let Howard go into space. Why would you stop him? It seems crazy.
Overall cool ep. Loved the references, the jokes, the guest stars. (And speaking of Wil Wheaton, when is BBT going to get Felicia Day on as a guest, or bit part even?)