Can ANY elf use a weapon with the word "elven" in its name? Example: can a elf druid wield a Elven Curved Blade? This is probably common knowledge, but I have looked for a long time and can't find the answer.
Yes & No
"Weapon Familiarity: Elves are proficient with longbows (including composite longbows), longswords, rapiers, and shortbows (including composite shortbows), and treat any weapon with the word “elven” in its name as a martial weapon."
"Weapon and Armor Proficiency: Druids are proficient with the following weapons: club, dagger, dart, quarterstaff, scimitar, scythe, sickle, shortspear, sling, and spear. They are also proficient with all natural attacks (claw, bite, and so forth) of any form they assume with wild shape (see below).
Druids are proficient with light and medium armor but are prohibited from wearing metal armor; thus, they may wear only padded, leather, or hide armor. A druid may also wear wooden armor that has been altered by the ironwood spell so that it functions as though it were steel. Druids are proficient with shields (except tower shields) but must use only those crafted from wood.
A druid who wears prohibited armor or uses a prohibited shield is unable to cast druid spells or use any of her supernatural or spell-like class abilities while doing so and for 24 hours thereafter."
Druids are not proficient with Martial Weapons, so no.
But nothing stops them from taking the Exotic (or Martial in this case) Weapon Proficiency (Elven Curved Blade)feat, so yes.