We offer free adult birthday party invitations that you can customize. Choose from a variety of modern styles and themes and plan the perfect party today. Check out our adult eCards: each card can be customized with your own message or image, and then sent for free via Facebook or email. Doozy Cards has a fun selection of free adult birthday cards to make them blush. Surprise your partner or sweetheart with a cheeky or funny dirty birthday ecard.