I am spamming your f-list like whooaaa
Here's what you give me:
1) one of my characters
2) another character played by you or me or anyone else

Here's what I'll give you:
1) a letter of some sort written to that character

You can choose a love letter, an advice with how to deal with another person, a venting letter about another character, whatever. If you want something written about a third character you will have to name that individual.