think of a place youve been to, home school or on holiday, then fill it with the enemy of your choice and have some sort of objective. for instance a hotel filled with aliens, ur objective is 2 fight past the aliens from ur hotel room 2 the bar for any sort of reason, be it bingo night, or u just wanna have a few drinks with barney and co. just take any normal place and give it some sort of wierd situation.