I love hanging with friends but don't mind being on my own from time to time. When heading out we're usually headed for a restaurant, a movie theater or pub. You'd be hard pressed to find me in a club, not on my own volition at least.
Whenever I'm stuck at home, I usually pick up a book, play a game, listen to some music, practice playing piano (emphasis on practice, a musical genius I am not) or watch a movie. When the sun's out, I grab my boots and go for a walk. On clear nights I like to grab my telescope and go stargazing.
Once a week I practice HEMA, which aside from being everyone's favorite purveyor of plastic goods and smoked sausages also stands for Historical European Martial Arts. Basically you dress up in protective gear and whack each other with swords. It is every bit as dorky as it sounds. Fun as shit though, plus you learn some valuable skills like "how not to impale yourself on the sharp end" and looking like a complete idiot in general.