Did something somewhat similar. Got drunk after final exams. We decided we were special agents and were rolling over car hoods/bonnets (like they do in chases). There was a van (think A-Team), and since it doesn't have much of a hood, I rolled off the roof instead.
Pretty sure I cracked or broke a rib (there was literally a loud pop). Couldn't sit up, cough, sneeze, or breathe deeply for about 2 weeks without intense pain. I never went to doctor though because I thought, "well, it's a rib, what are they gonna do? Put a cast around my whole body?"
Now I have discomfort every day, and pain between 2-3/10 after any sports. Tough when your youth idiocy catches up with you! Felt so invincible back then.