This is pretty much what cave-dwellers used before Twitter was invented.
These speech bubble chalkboards are perfect for use in wedding photos or to stick to your wall. The large size makes an awesome quotes board if you let it hang out in your lounge.
A shaped blackboard can make a great photo prop! 6mm thick (nice and light) and finished with several coats of premium, non-toxic, chalk paint. All shaped boards come with Velcro dots for easy wall mounting if desired.