A long time ago, when I first got involved with pen palling in a traditional sense, a few of my pals were much more involved than I was. I started getting tiny little "booklets" with magazine cutout covers and decorated pages, each page with a different address and someone's likes and dislikes listed.
They called these "friendship books", and the whole idea was to sign a page with your name and address, and to send them off to another person, who would then do the same, until the booklet was full. At that point, the last person in line would mail the book back to the person who made it (or, in some cases, to another person that the maker had created it for).
By doing this, not only is it kind of fun to decorate a page with some kind of picture or collage that "represents" you or the theme of the booklet, but it's also a great way to find new pen pals -- just look over the entries by the people before you, and find someone with interests close to yours. And if the right people were participants, when you get the booklet back, you have a great little book of art.
I found a few sites on the web that talked about these booklets recently. However, the term "friendship book" is something completely different now -- most of the time they just mean poorly constructed stapled papers where participants just put a return address label inside to represent themselves. Despondent about this, I pretty much gave up hope for the creative things I remembered.
Then someone mentioned DECOS, or, "decorated friendship books". THESE were the things I remembered, and with some groups of swappers, they were much better even than what I'd gotten ahold of before.
The creativity that some artistic souls put into these things is staggering. Artists put together themed and unthemed booklets with creative bindings, gorgeous materials, and wonderful entries by participants. Quality decos are kind of few and far between, as is ANYTHING of quality, but when you get one, it makes up for all the mediocre things you've come across.
The two galleries below can show you more about these decos. The "mine" gallery shows booklets that I've been making, and "others" shows pages that I've been putting into other people's books. (Right now, I'm not overly comfortable with scanning someone else's work, unless I have express permission. If I get said permission, I'll pop those up in a separate gallery at a later time.)
Under "bindings", you can find out how to make some decos for yourself, and some how-to ideas for binding your booklets creatively. And the links section has a ton of sites, mailing lists, and clubs for people who swap fb's and decos. The glossary/abbreviations section (under pen pals) has some useful terms for you to know in the lingo of pen palling.
It's an extremely addictive hobby that can go hand-in-hand with your letter writing, or can be separate, as well, depending on whatever level of participation you'd like to initiate.
Decos are definitely cool.