Superbee mentioned bugle calls in a recent post. It reminded me of helping a US Scout Troupe introduction to harmonica a while back. The US bugle calls are pretty easy to play using blow only notes. Taps is a good one to start with on blow 3.
Superbee, best wishes with your upcoming bugle calls. If you start getting choked up (I know I would) it will just add a nice vibrato.