Code
Nightlies
Nighlies are build once a day at 00:00 midnight, local server time.
The nightlies' server is located in the U.S. (Michigan) and it is using this as server's time zone.
Example
What does it mean for people from other timezones with respect to the included source changes from 1 if the nightlies timestamp says "30-Aug-2011 00:05"?
Q: What is the threshold for those "changes" notices (http://code.google.com/p/libgdx/source/list) if you want to be sure that they are included in the available nightlies download?
A: Nightlies hosting server is located in the U.S. (Michigan) which has UTC/GMT -4 hours ATM. If I have UTC/GMT +2 hours then nightlies were build 06:00 AM (my local time).
If it was 11:00 AM here right now I can consider all "changes" that are timestamped as more than "5 hours ago" ago as included in the libs.
Nightlies download
SVN sources checkout
http://code.google.com/p/libgdx/source/checkout
Building .jar files yourself
Of course you can always build the jars out of SVN sources yourself with some amount of work: