Here's an interesting one that arrived in the mail today.
I bid on this card at auction because of the yellow Marine-Postbüreau label that is attached. When Feldpost to the German colonies was undeliverable, it was returned through the Naval Post Office (Marine-Postbüreau), where the label was applied.


Once I got it in hand, however, a couple additional interesting things were revealed. The arrival postmark from Windhuk, Deutsch-Südwstafrika, is a rare one. The "b" canceller was a reserve canceller that was primarily used on internal postal matters, so this is a nice find.
But the real scoop lay in the recipient and the text.
The recipient was Gefreiter (Corporal) Paul Fett, of the 5. Kolonnenabteilung (5th Transport Column), with the German forces fighting the Herero and Nama people in Deutsch-Südwestafrika. Prior to deploying to DSWA, he was with the "Graf Bose" Infantry Regiment (1st Thuringian) Nr. 31.
On 24 February 1906, he was severely injured after being kicked in the head by a horse.

Then, on 30 July 1906, he was awarded the Military Badge of Honor, 2nd Class.

The card was then sent from Charlottenburg on 9 August 1906, with text that says, roughly, "Dear Sir! I am pleased to announce that you were awarded the Military Badge of Honor on 7 August. My best congratulations and greetings."
Unfortunately, by the time it arrived in Windhuk (27 October 1906), Gefreiter Fett was no longer with his unit – I couldn't determine if he was evacuated back to Germany, in a hospital in DSWA, or deceased – so the card was returned as undeliverable.