I used to LARP back when it wasn't called LARPing.
We called it Ampgard, although I think that was the name of the rule system we were using.
Tons of fun to beat each other up with foam weapons.
Or watching someone scream 'LIGHTNING BOLT' ten times and then throw a yellow streamered hackey sack at people.
Seriously, if you can get over the awkward feeling of 'What about what other people think of me?', it's a fantasticly fun hobby that keeps you active at the same time.