When they were trying to launch a model of rocket in the park, they saw Dennis Kim drinking with girls and totally messy.
They kind of feel bad about what they did to him because they thought it resulted in ruining his life.
But Sheldon seemed to have a different opinion, he thought why Dennis fell in the situation right now was because he was weak.
Howard said the new Star Trek film is going to have a scene depicting Spock's birth. But Raj said he was more interested in a scene in depicting Spock's conception.
Trek: when you trek somewhere, you go there slowly and unwillingly, usually because you are tired.
Going another country difficultly.
depict: describe something in painting or drawing.
conception: an idea you have in mind towards something
frisk: search someone in hands to see if they have carry weapons with them.