http://nehrim.de/
It's pretty cool. It's a completely remade Oblivion, with a new leveling and skills system. It tries really hard to be Gothic, but with Oblivion's engine. Also, all the dialogue is spoken in German by professional voice actors. Doesn't bother that much, since you can download the English version with all-English texts.
The whole map, world and lore has been remade, it's got nothing to do with the TES universe. I recommend it. The action is still quite Oblivion-ish, but it has a lot of potential for a fan-made modification.
Get it, try it, share your experience.
Nehrim - German mod for Oblivion
