When was the last time you sent someone a letter, and which letter was it?

Today.  I sent them the "F" letter, followed by those 3 other letters... UCK....which was then promptly followed by another 3 letters which were...YOU. 

The letter was $. I recently sent a letter to the governing body of which I raced motorcycles back in the 70s. I commented about the inequity of the purses paid to today's racers. The racers are only getting about one sixth of the ticket sales. It used to be about half. Anyway, I heard a rider-representative claim last week that an extra $4000. was being divided and added to each racers' pay envelope. Not exactly what I was hoping for, but it is a beginning-------

i have penpals i sent letters to

I just put it in the envelope.  It's the one where registered mail will be used.  ;)