"Find a shoebox, or a storage bin, or any cardboard box you have laying around. Fill it up with bricks, big blocks of iron, or maybe cement. Tape the box up with everyday packaging tape. Use a junkmail's postage-paid envelope and tape it neatly to the top cover of the box. NEATLY. And mail it off. Envelope revenge!"
http://www.officeofstrategicinfluence.com/bulkmailer/