Asian cultures have a long history of using masks during celebrations (including during Chinese New Year festivities, when wearing Chinese zodiac masks is popular). The mask worn is determined by the year (e.g., in the Year of the Dragon people wear dragon masks; in the Year of the Dog, they wear dog masks).
Chinese actors also wear masks for theatrical performances. Chinese theatre masks are painted with colours and patterns specific to each character; many of these colours and patterns represent traits of the character represented. It's a simple process to create your own Chinese mask with a little paint.
Find several pictures of Chinese masks (see the References section). Decide which one you like the best and print it out for a reference.
Spread out old newspaper on your work surface. Place all of your materials, including your picture, on top of the newspaper.
Paint the face mask with a coat of white paint and allow it to dry for an hour. This will "rough up" the plastic surface so it will hold your colours better. Plain face masks with elastic ties are available at craft stores.
Sketch your designs onto the mask, paying attention to the details on your reference picture. Any mistakes can be lightly scribbled out, as they will be painted over.
Paint the sections of the mask. Begin with the sections in the centre of the mask and work outward. This will help avoid smudging the paint with your wrist as you go.
Allow the mask to dry for about an hour. If the mask is no longer tacky, it is ready to wear or touch up with another coat of paint.