Penny's decision to go back to school was also a significant moment. It showed her determination to better herself and grow as a person. Her struggles and successes in her academic journey were quite inspiring and added a new dimension to her character that had nothing to do with sexual content.
Another great moment is when they participate in group activities together with the guys. They add a different dynamic to the group, and their friendship helps bridge the gap between the nerdy guys and the more social girls.
There are numerous funny moments. One is when Sheldon tries to teach Penny about physics concepts in his own unique, overly - complicated way. His facial expressions and the way he gets frustrated when Penny doesn't understand are hilarious. Another is when Howard wears his astronaut suit in inappropriate situations, like when he goes to a regular party. It looks so out of place and makes everyone around him react in a really funny way.
One memorable moment was when the characters were all carrying heavy things and couldn't use the elevator. They had to struggle up the stairs with all their stuff.
Probably the time when Raj took a girl on a stargazing date. He was so nervous and excited at the same time. He tried to show off his knowledge about the stars but ended up getting tongue - tied a bit. It was a really cute and memorable moment that showed his love for stars and also his awkwardness around women.
As far as I can remember, there is no such Penny wedgie incident in The Big Bang Theory. The series was filled with different kinds of comical situations. For example, there were Sheldon's idiosyncrasies, Howard's attempts to pick up women, and Raj's selective mutism. But a wedgie incident for Penny just doesn't seem to be part of the storylines.
The scientific adventures of the characters are also a big part of it. Their work at the university, their research projects, and their attempts to make scientific breakthroughs. Like when they collaborate on a project about string theory or try to solve some complex physics problems together.
Penny's friendship with the whole gang is a great storyline. She is often the bridge between the nerdy guys and the more 'normal' world. For example, she helps them with social situations and they, in turn, help her with things like knowledge and different perspectives.
Another aspect could be Penny's family. Fanfiction could explore what happens when Penny's family from Nebraska visits and how the guys interact with them. Maybe there are some comical situations where Penny's parents misunderstand the guys' scientific work, and Penny has to mediate. These stories can be really interesting and family - friendly.
One positive change was her growing acceptance of the guys' geeky interests. She started to enjoy things like comic - con and science - related stuff. Another was her becoming more responsible, like when she got a better job and started to manage her money better.
One appropriate topic could be their adventures in scientific experiments together. For example, they could be collaborating on a project where Penny's practical skills and Sheldon's theoretical knowledge combine in a comical yet productive way.