I found a nice thorough but concise article about Ramadhan in Indonesia on the expat site, so I thought I'd post the link to it since a few people have been asking how it's likely to affect their trip, etc.
No doubt there's a few lurkers who seem to think any Muslim celebration is a big festival of hating Whitey. I hope they read this and get a clue.
Ramadhan starts tomorrow. It ends with Idul Fitri on November 5th. If you need to book flights/busses/boats/buggies for travel within Indonesia during the next month, do it ASAP, or you may need to travel piggy-back on a monkey.
http://www.expat.or.id/info/lebaran.html