You will need:
11" x 14" or 8 1/2" x 11" Poster Board 
Christmas Cards or if not for Christmas use Birthday Cards or any occassion cards you have
Glue
Contact Paper 
Markers
Scissors 

Instructions:

Cut out pieces from your cards or use them whole. 

Glue all the pieces in place. Let dry. 

Place the contact paper over the top of the placemat and the back. 

Personalize the placemats by writing a name on each if desired.