Here is a super-easy card that will certainly impress your friends!
1) Cut a piece of 12″ x 12″ cardstock in half
2) Score at 4″ and 8″
4) Cut off one corner in a triangle shape
5) Use the cut-off triangle piece as the pattern for the other triangle cuts
7) Use a 6″ x 6″ envelope for mailing (requires extra postage)