The guys of Big Bang Theory buy the prop time machine from the film The Time Machine. Leonard jumps in and sets the machine to March 10, 1876 the date of the famous first phone call. They proceed to argue over the fact that they all want to go but they would not be able to all fit into the small lab and agree that they should travel into the future to get a cloaking device first. Here’s their conversation about the cloaking device.
Sheldon: First go into the future and obtain a cloaking device.
Rajesh: How far into the future?
Sheldon: If I remember correctly Captain Kirk will steal a cloaking device from the Romulans on stardate 5027.3, which will be January 10th 2328 by pre-Federation reckoning.
As a collector and a fan that plays with their toys the scene that followed was hilarious with the four guys acting out the high speed action that goes on around Leonard while traveling in the time machine. Penny comes in to tell them all how pathetic they all are for still playing with toys. Leonard then goes on to re-evaluate his life, his maturity and his collection. (Bad Penny.)
The Nerdvana that Leonard has created is disappearing as he is packing up his collection to sell to the comic book guy down the street. All his friends want to buy it off of him but he refuses saying it will hurt their friendship if he sells his stuff to one over the others. They try to stop him and he pulls out a Playmates Star trek figures and threatens to open it. 
Sheldon: No I can’t let you do this.
Leonard: Sheldon, get out of my way.
Sheldon: (Grabbing a sword from Leonard’s box) None shall pass.
Leonard: Okay. I did not want to do this, but…I have here the rare mint condition production error Star Trek: The Next Generation Geordi Laforge without his visor in the original packaging. If you do not get out of my way I will open it.
Howard: Okay, man be cool. We’re all friends here.
Penny comes out and Sheldon lets her have it.
Sheldon: You hypocrite.
Penny: What?
Sheldon: Little miss grown-ups don’t play with toys. If I went in to that apartment right now would I not find Beanie Babies? Are you not an accumulator of Care Bears and My Little Ponies? And who is that Japanese feline I see frolicking on your shorts. Hello Hello Kitty.
Penny then apologizes to Leonard about the day before and he just about asks her out when a hunky guy comes up and goes into her apartment with her. Leonard grabs his toys and heads back into the apartment saying, “My turn on the time machineâ€.