I know it's trivial, but it's a fun challenge for the obsessed.
Legolas has magical arrows. The fletching (that's the feathers on the end) changes color quite frequently. It's easier to see this when you can see his quiver, as they are moving fast when he fires them, but when they embed themselves in targets you can see the feathers again.
This happens in each movie, but I believe it happens most in this one.
All right. Sadly, I don't own any of the movies/ DVD's, and I have never had the opportunity to pause a friend's version, so I don't know HOW MANY times this happens, or HOW MANY colors there are. I promise that at the next opportunity to watch it, I will take a notepad and write it all down, and you won't have to drop me in boiling oil for not having specifics (of which there are many, anyway).
My pathetic excuse is that I thought this could become an absurd sort of contest, since I'm not a true LOTR geek.
So a challenge to all LOTR geeks: Find out how many times an arrow changes color where it absolutely is impossible to do so, bonus points if it changes color in mid-flight. And we could make a list of colors (stripes are included, ex. the arrows that are yellow w/ brown stripes.)