Important note: ownCloud 7 or ownCloud 8 will be last version to ship the master branch's codebase. It will be replaced by the rework branch. If you want to implement new features, please strongly consider implementing them based on the rework branch's codebase.
Just clone this repo into your apps directory. Get the lastest version of master:
git clone git://github.com/owncloud/calendar.git
cd calendar
Get the lastest version of rework:
git clone git://github.com/owncloud/calendar.git
cd calendar
git checkout rework