I turned 18 5 weeks ago (In Aus the legal age is 18). For me I went out to the city, got on the mings, got trashed, went clubbing was outstanding.
Most of the greatest have ridiculously strict routines if you want to get technical about it. Even B/C level guys like Maher ran 20 friggin' miles a day. Spartan stuff. I bodybuild, so color me biased.