My favourite episode with Penny’s friend Zack.

Zack: I wanna see the laser.

Penny: But what about the party?

Zack: Its a surprise party, it doesn’t matter when we get there.

 

Zack: Whoa, is that the laser? It’s bitchin’.

Sheldon: Yes, in 1917 when Albert Einstein established the theoretic foundation for the laser in his paper ‘Zur Quantentheorie der Strahlung’, his fondest hope was that the resultant device be “bitchin'”.

 

Leonard explains they are doing an experiment where they bounce a laser beam off the moon.

Zack: One question; how can you be sure it won’t blow up?

Leonard: The laser?

Zack: The moon.

…

Leonard: Don’t worry about the moon, we set our lasers to stun.

Zack: Smart.

Leonard: Now, we’ll see the beam when it leaves but it won’t be strong enough when it comes back to be seen by the naked eye.

Zack: Naked, heh heh heh.