Last year I made laser-cut folded lacy wedding invitations.
I designed them over the course of many interations and cut them out using the laser cutter at Sector67. Each invitation took 33 minutes to cut out and assemble.
I designed a new font for the address part of in the invitation where the inverse of the letters gets cuts away. This way you don't have to worry about the middle of your Os dropping out like when you cut out the letters themselves. You can download my font here. I made the "<" symbol correspond to a half circle and I put that at the beginning and end of every line of address to give it a rounded-edges.
A key step was getting the invitations thin enough to go through the regular mail. If they were too thick, they had to be shipped as a parcel. I tried mailing a test invite as a parcel, and it never arrived, probably because it was too small really to be a parcel and got lost in the shuffle. In order to make them thinner, I ironed them.
There were failed ideas along the route to this design, as you can see in this video.
In the end we had a perfect delivery rate through the USPS with 70 cent stamps and our guests were pleased. We put the return address on the stamp themselves, and they did function as return address.