T hrow in your language, your slang. Nothing says more about who you are than the way you speak. Throw in your symbols. Mathmatical notation, chemical formulas, and graphs will become the heiroglyphics of the future. Throw in the latest joke you heard.
Currrent humor tends to reflect current times.
I just had my cholesterol checked. The doctor said it was 911. 100 years from now, I wonder if people will understand that joke. As it turns out, there is virtually no evidence of ancient humor. They surely must have had humor, but no one ever thought of preserving it.