I write Android tutorials for Tuts+ http://hub.tutsplus.com/authors/sue-smith
and am starting to create GitHub repos for the source code.
Lots of the tutorials were written some time ago so the techniques are often out of date. However, the repos will initially use the code exactly as it appeared in the tutorials, so that anyone who read a tutorial will already be at the same starting point as the repo - any changes made after that will therefore be clear to see.
Hopefully sharing the code on GitHub will make it easier for people to use (and maybe contribute to) the demo code. I will ideally update at least the more substantial examples when I have time..
Here's the first one anyway, on using the Text to Speech library.