For future reference: police and local embassy. Not necessarily in that order. The embassy can issue new papers and/or effectively a temporary passport if you're not hanging around (they can issue full passports but it'd take a lot of time) and you'll need a police report for the insurance.

All festivals have a list of ticket holders these days so if you'd done all that and presented the police report and temp papers you could probably have whimpered your way into getting a replacement at the ticket office if you'd gone a little while before you'd otherwise have been able to get in.