Hi! :) I'm building a big 7segment clock with an Arduino at the moment and so I needed to use a RTC. To test the RTC and to do some other field experiments I've decided to create a breakout board for the MAXIM DS 1307. It should include a backup-battery, a crystal and the pullup resistors to be connected easily to an Arduino.
And here you can the the results of about an hour of creating, etching and soldering:
It's running the example of mattt's DS1307 library and it's doing very well in keeping time :D
The EAGLE project file can be found here
I hope you like it and you can use it for your RTC projects :)