I don't think there really is any. Only if you know the music directors personally.

But to answer more seriously: Usually, I hear of people getting sheet music to certain shows, or what have you, just by carefully listening and playing the notes aloud. Of course, that takes a lot of time and skill, but it's possible. Then, just fine tuning it from there. But to go back to my original answer, you could use the internet to find the score, or whatever they call it, or find someone who already did the hard work for you, and hopefully has the music to share. Bottom line: You have to do some searching.

I know how to play the first part of the theme!

The piano. I can pretty much play the short version of the theme song, one of the songs out of The Beach, and the theme for Lake Laogai.

I learned the four seasons song on my bass.