various arcane bits of legislation exist... not all of them are enforced or valid. it depends where you are & what you're doing. there are shitloads of outdoor parties in the UK, but the weather and the size of the place mean that there are lots of squats and warehouse parties as well during the winter months.
what i was loosely getting at is that people here have been to an incredible number of parties in incredible locations... outdoor festivals in the (absolutely stunning) Azores, the Mount Fuji festival, bush doofs in the most gorgeous Australian forests, parties in palaces outside London, private gigs on tiny Greek islands, desert parties in California, underground clubs in New York, Hungarian psy extravanganzas, beaches in Goa, clubs in Tel Aviv, festivals in the French Alps...
there's a whole world of experience out there.... all i can say is that i want to try it all meself :D