My sincere apologies to whoever sent a card to the address for the Walter Reed Army Medical Center I posted last month. It turned out the address was incorrect, as the cards I sent were returned to me. :( I am guessing yours has been/will be returned as well. I should have made sure the address was right before I copied it from the source I did. I'm so sorry. Here is the correct address if anyone is interested.
A Recovering American Soldier
c/o Walter Reed Army Medical Center
6900 Georgia Avenue, N.W.
Washington, DC 20307-5001
Hopefully this address will work!