Whenever someone tries to out-geek me, I challenge them to show me their stamp collection. Unless they can prove to me that they, too, stayed home from a party in high school to work on stamps, they are relegated to second place when it comes to the international geek awards.
My stamp collection isn't all that cool, really. I inherited my brother's collection when he graduated from high school, and I collected world stamps sort of haphazardly through college. In grad school, I started collecting British India stamps. I even wrote a paper about the 1937 issues (yeah, that was the paper that proved to everyone involved that I had no future in academia). Catherine started collecting around then, jacking all my U.S. stamps to add to her own collection, and I started working on Russian and Soviet stamps. I've got a pretty solid late-Soviet collection: I've got every run from 1985-1992, for obvious reasons. My 1948-1985 collection is kind of spotty, but still interesting. For some reason, my 1918-1948 volume is almost completely blank.
Anyway, today I was sorting some stamps, and I realized I have some pretty neat things that I acquired accidentally. My favorite stamps are the ones from tsarist Russia. My oldest one Russian stamp is from 1889. My oldest British stamp is from 1882, a 14-dot Queen Victoria 1d. Catherine's oldest stamp is from 1857. She's got some others from the Civil War, and a couple from right after.
The neat thing about stamp collecting is that you don't have to try very hard to find neat things. I don't even remember how I got my tsarist stamps, they just sort of showed up one day, probably in a general lot. Also neat is how philately skews your perception of the world. Since my world collection is built around my brother's old album, which he got in 1971, my knowledge of geography is totally whack. Three quarters of the countries in the original album don't exist, and I have to sit and think about how I want to re-categorize the world every time I get a new stamp. How do I handle the Balkans? Do I continue to put stamps under the old countries, do I buy new pages, do I just stick them on blank pages and try to remember where I put them? Russia is particularly challenging with all its imperial landgrabbing, and all the redrawing of the borders after every war, and I get a kick out of it.
Stamp collectors/dealers in general are nice people. It's a great industry. Stamp dealers will send you lots worth hundreds of dollars in the mail, and trust that you'll pay for the ones you want to keep and send back the ones you don't. How cool is that? The guy who owned the hobby store I used to go to in Oregon used to send me home with a huge bag of stamps, trusting me to bring them all back after I'd picked out the ones I wanted, and to tell him honestly how many I kept at home. I know the stamps aren't exactly priceless treasures, but it's still a nice way to do business.