A Telegram (-STOP-)
Yes, a real telegram (or as real as a telegram will be today). Can you believe this was the email of the day for some? I have sent a few since last Summer but it's such an elating feeling when it's on my side of the mailbox. Liz from srslyliz sent me a telegram last November. I've been meaning to scan it for months. Now, I'm packing and finding so many awesome things, including this love letter. Thank you, Liz!
The telegram is less than $6 to send (you can't put a price on giddiness, folks, this telegram is priceless), and you can write anything you want. You can send your telegram through the creative group of people for the love of analog, Telegram Stop.
They also have an iPhone app to make life even easier, download it here.
UPDATE: You can get 10% off with code CITYLIGHTS. Hoorah!