How do You Have fun and not Use Drugs Alcohol and sex ?

I Have Been 21 for 3 months and my friends are turning 21 in June and they are super exited about going to Vegas getting wasted and having no recollections of the events from the night before, they want to get in fights and essentially be assholes all weekend... this makes me wonder is this what happens once we are 21 seriously I'm not really interested in drinking smoking or being in relationships, i have Responsibilities i work to pay for my school my friends just go to school we went to see Tron :Legacy for my Birthday and i had fun what else do people do besides that for fun what do you do ?