Penny humiliates Leonard about his toys and he decides he's going to get rid of all his nerdmabilia in this episode of The Big Bang Theory.
The guys gather round Leonard as he sits in his time machine which arrive. The time machine is, of course, the prop from the 1960 movie that he bought off ebay.
Sheldon has a nightmare in which the Morlocks attack him when he uses his time machine from the 1960 movie.
The boys gather around Leonard as he gets the winning bid on the time machine from the 1960 movie <i>The Time Machine</i>.

The Big Bang Theory Season 1 Episode 14 Quotes

Sheldon: Why'd you set it for the day before yesterday?
Leonard: Because I want to go back and keep myself from getting a time machine.
Sheldon: You can't. If you were to prevent yourself from buying it in the past, you would not have it available in the present - travel back and stop yourself from buying it, ergo you would still have it. This is a classic rookie time travel mistake.
Leonard: Can I go back and prevent you from explaining that to me?
Sheldon: Same paradox—if you were to travel back in time and, say, knock me unconscious, you would not then have the conversation that irritated you, motivating you to go back and knock me unconscious.
Leonard: What if I knocked you unconscious right now?

Raj: Too bad, I called dibs.
Wolowitz: You can't just call dibs.
Raj: I can, and I did. Look up "dibs" in Wikipedia.
Sheldon: Dibs does not apply in a bidding war