I haven't done this yet. I was going to do the 6x9 rectangle thing, but that was so...detatched. It wasn't really personal, you know?
Well, I was chatting on the message board I'm constantly at and someone told us about a wonderful website: AnySoldier.com.
AnySoldier is not a middleman where you send stuff and they send it on. It is a place that brings together many military "contacts", men and women who are stationed overseas. These contacts provide their mailing address and a list of what to send. When they get a package with the line "Attn: AnySoldier" below the contact's name on the mailing label, they give the package to one of their men/women who does not receive or infrequently receives mail.
I think this is a fantastic idea. I can send things directly to specific people who will see that the useful and fun things I sent will be recieved by someone whose day will be brightened in an otherwise gloomy situation. I am SO doing this!