'You built a time machine out of a DeLorean?' Marty McFly asked Doc Brown on the screen in front of Penny and Sheldon.
'I love this part,' Penny told Sheldon leaning into his chest; 'I always wanted a DeLorean time machine when I was a kid.'
Sheldon shook his head, 'I've always thought the DeLorean time machine was much too obvious for any kind of meaningful time travel to anytime where cars were not readily available. A TARDIS is a much more realistic form of time machine as it has chameleon circuit to blend in with its surroundings and it also travels in time and space which is far more useful.'
Penny sat up and looked up at him, 'but isn't the TARDIS's chameleon circuit broken? So a car will always be easier to hide than a giant blue box.'
'I'm sure if the Doctor were real he would have fixed it,' Sheldon assured her.
'That TV show has been running how long, and they've never fixed it,' Penny shrugged her shoulders.
Sheldon shot back, 'they don't change it because the blue police box is iconic.'
'Like a DeLorean time machine, isn't!'
'Not as iconic as a TARDIS,' Sheldon challenged her.
'Yeah, right! I'd still rather have a DeLorean instead of a TARDIS,' Penny told him crossing her arms over her chest.
'Although, an original Time Machine invented by H. G. Wells in the 1895 novel The Time Machine and the basis for both The Time Machine films would probably be my vehicle of choice,' Sheldon corrected him self, 'even if it is large and obvious in any surrounding, it is still the original and nothing beats the original idea.'
'Nothing but a DeLorean with a flux capacitor,' Penny corrected him.