I ordered the supplies from Cards and Pockets. We used the Signature Pocketfold kits in Milk Chocolate and Turquoise. (Our actual colours are a dark teal and espresso brown; these two came the closest out of everything I've seen in any invitation company.) I designed the layout for the invitation and the enclosures myself (with some inspiration and some clip art from One Heart Weddings) in Microsoft Publisher. My dad helped me print them (and cut/trim, which was a huge job). Youngest helped me sort them. I glued them all together, with some help from Mat. I cut the blue bands from matching cardstock, and used special modern sealing wax to put the Clan Gordon crest on the outside.
I also dug out my (t)rusty fountain pen to do the addressing. (Those who are receiving their invitations in person are getting proper calligraphy; unfortunately, I am not sufficiently masochistic to address all 80+ invitations in full calligraphy. I will probably do all the place cards by hand, though.)
According to the website, I have a mere 96 days left.