In lieu of actually providing content myself, it might be worthwhile to point out some interesting articles and items that other people have published.
Over on the Tairis site, Seren has given us an excellent four-part article detailing the virtues of Gaelic tradition and culture. Of course, the rest of her site is also well worth reading.
Here's a site which gives a short overview of Proto-Indo-European religion.
On the NEOHEMAS blog, there's an article discussing how to train for Irish-style stickfighting without a partner.
Speaking of Irish stickfighting, here's a place that makes sticks appropriate for fightin'.
Black Dogs have a number of features in common with werewolves in Europe. Here's some more about them.
Here's an implementation of a lunisolar calendar derived from Celtic antecedents.
In the story of Tam Lin, the titular character is part of the fairy procession. That procession has some relation to the Wild Hunt connected to werewolves of European conception.
Some people are trying to revive the Gaulish language.
There's an interesting article discussing a feminist perspective on werewolves in pop culture. This is a useful perspective on an aspect of the werewolf concept as it is affected, and as it affects, the modern world.
Here's a look at how information about folklore subjects (in this case, werewolves) can get switched around and create a mistaken idea. A short note in O'Donnell's Werewolves (aka Werwolves) got changed around, a definite location added, and with some judicious mixing in books and then on the internet we end up with a fallacious "clan" of werewolves on the Isle of Lewis.