Note: For those looking for it, I've put up an official page with links to all entries here.
One of the things that I still find incredibly fun about being a scientist is the ability to "touch" history, in the form of the original publication of now famous scientific results. I'm reminded of my undergraduate days, when a classmate and I were discussing the topic of Čerenkov radiation, which had become relevant in our high-energy physics discussions. We didn't completely understand the idea, so the next day my classmate came in with a photocopy of Čerenkov's original (well, translated) 1934 paper. That was the first time it dawned on me that, as scientists, we could go right to the "source", so to speak, and in essence learn about science from the famous people who performed it.
There's a lot more to learn in going to the source than one might think. As Tom at Swans on Tea observed recently,
The “materials at hand” is one thing that continually amazes me. I read details of some century-old experiment and am reminded that their apparatus and supplies were hand-crafted, often in the same lab. You read about Rutherford doing alpha-scattering experiments in pure nitrogen. Did he order a tank of compressed nitrogen from the local welding-supplies shop, like I do? Of course not.
The nitrogen was obtained by the well-known method of adding ammonium chloride to sodium nitrite, and stored over water.
(My well-known method involves the internet and a credit card)
My "challenge", for those sciencebloggers who choose to accept it, is this: read and research an old, classic scientific paper and write a blog post about it. I recommend choosing something pre- World War II, as that was the era of hand-crafted, "in your basement"-style science. There's a lot to learn not only about the ingenuity of researchers in an era when materials were not readily available, but also about the problems and concerns of scientists of that era, often things we take for granted now!
(I've already got my paper picked out, though I miscalculated a bit: I thought it was a straightforward experiment that couldn't be more than a two-page paper, but it's about 40 pages - and in German!)
P.S. Hopefully it was clear from the original post, but my "challenge" extends to sciencebloggers of all branches, not just physics bloggers: I'd be really interested to read about some of the landmark papers in biology, chemistry, and math, too!