Peeps are visitors in RCT3. They come to your park and ride certain rides (based on the ride type preference). There are also VIPeeps who come to your park and ride your rides aswell. You MUST please them to complete certain objectives.
Peep Creator Edit
A new edition to RollerCoaster Tycoon 3 is the Peep Creator. This allows you to create custom made peeps to visit your park. Peeps have age groups (another new addition to RCT3) which are Child, Teenager, and Adult. They also have ride intensity preferences. You can change the face/hair/skin, shirt, pants/skirt, and shoes.