Are you stuck and don't even know what to begin to write? Here are a few ideas . . .

Angels
Secret Agents, Spies
Cowboys & Indians
Circuses
Gangsters, Mobs
Zoos
Music, Bands
Theatrical Performances
Sports (basketball, soccer, horseback riding, ect...)
Geographical locations (jungle, desert, ocean, ect...)
Animals
Haunted cities, urban towns, ect...
"Olden" days
Futuristic events
Rodeos
Oceans, Sailing
An event in history
The Internet
Runaways
Trains, Planes, and Automobiles
Armies
Servants, Butlers, Maids
Rich Eccentrics
Theme Parks
Camping, Hiking
Deep Sea Divers
School
Princesses, Princes, Kings, Queens
Robots
Aliens, UFO's, Extra Terrestrial
Annoying Siblings
Weather Disasters
Friends