Received a call early on Saturday morning and did not answer as I knew no one at this number or the origin which was Gaithersburg, MD.

I have been receiving a call from Gaithersburg, MD as well, they called this morning @ 11:41am and the last couple days of course a message is never left on my machine. I wished that they would stop calling my house.

240-751-4750 has been calling multiple times a day for weeks.  I don't answer the "local callback" caller I.D. & there's never a message.  I guess being on the do-not-call list has more loopholes than I thought.

Received four or more daily calls from 240-751-4750.
Caller ID "Local Call Back".
Unusual in that it rings three times, then quits, unlike most solicitors that ring all the way into voice-mail.

Called it back... "Military Order of the Purple Heart".