During the first season, Penny has a Halloween party and invites the boys. During the party scene, a few individuals can be seen on the balcony outside Penny's window dancing and conversing. No other episodes show anyone outside her window or indicate that a balcony would be there.
More likely there is a fire escape staircase there.
More likely there is a fire escape staircase there.
Since Raj is at a Halloween party where people are drinking, he could drink alcohol, and therefore be able to talk to women. However, he would discover this only in the 8th episode, "The Grasshopper Experiment". Raj decides to "start drinking" in that episode due to his depression over being unable to talk to the woman his parents have set him up with. So at this point, he was possibly a teetotaler.
When Leonard asks Sheldon to be his wingman, Sheldon responds with "I'm much more suited to being the guy from the FAA analyzing wreckage". The FAA doesn't investigate air crashes. That's the job of the NTSB (National Transportation Safety Board)
When the guys attend Penny's party, there is a guy with a hard hat on. Studio Lights and several other pieces of studio equipment are reflected in his hard hat.
Sheldon mispronounces "manga", the Japanese word for 'comic book' or 'graphic novel'. For it to have been pronounced as Sheldon had done, it would have to be spelled "meinga", which is meaningless in Japanese.
Homo habilis is properly pronounced with the stress on "hab" instead of on "bil" as done by Leonard and Sheldon. Ironically, though Leonard was insulting Kurt by referring to him as H. habilis, Leonard is actually closer to the average height of H. habilis which was 4'3".
As Penny is from the American Midwest (Nebraska), she would not be surprised to have people start showing up for her party at 7:00, even though most of the invited guests are from the West Coast.