That's Katee Sackhoff and that's George Takei. Both guest star as themselves on the episode "The Hot Troll Deviation."

The Big Bang Theory Season 4 Episode 4 Quotes

Wolowitz: I love watching Raj and Sheldon try to work together.
Leonard: Yeah, it's like if Alien and Predator decided to go partners in a Jamba Juice.

If we lived in the world where slow moving xenon produced light youd be correct. Also, pigs would fly, my derriere would produce cotton candy, and the Phantom Menace would be a timeless classic.