From The Big Bang Theory, Season 5, episode 15 "The Roommate Contradiction"
Leonard signs out of his roommate agreement, reducing himself and Sheldon to mere acquaintances, while Howard tries to think of a cool astronaut nickname for himself.
Here the power goes out, and Sheldon tells Leonard and Penny that the California Power and Light Co. recommends glowsticks over candles during a power failure.
"You call that a glowstick?"Leonard asks Sheldon, as he goes into the closet and activates his Lightsaber prop, telling him "Now THIS is a glowstick", all the while mocking Sheldon's tiny glowstick....LOLz