I purchased kraft note cards with envelopes, owl ribbon, an owl rubber stamp, and a moss green stamp pad. (Later, I purchased a chestnut brown stamp pad, because the green ink didn't show up very well.)
Don't make the same mistake I did and run out of ribbon halfway through the project! I misjudged how much ribbon I would need. I knew the roll contained nine feet of ribbon, and I thought (guessed) each card would require a foot of ribbon...
enough on one roll to make eight cards. Wrong! I had to use 16 inches of ribbon for each card to make the knot on the front look right.
Here are photos of the finished invitation.
I printed addresses on labels using moss green ink and the same font (Curlz MT)...
and affixed "Celebrate!" postage stamps.
Also, I added an owl sticker to the back of each envelope.
Additional party details are forthcoming!