Good stand-up comedy for high school..?

I am auditioning for Culture Night at my high school in Houston. As the name suggests, it's about culture but anyone with a good talent can perform. I decided to stand-up comedy, which will be very hard to do because most stand-up comedians use inappropriate topics and use language. This is high school, so I need to keep it clean yet funny like Bill Cosby. Does anyone have any topics or tips on this? Any current events or icons, or anything? I would greatly appreciate it your help! Thank you.