You can clone with
HTTPS or Subversion.
Since we implemented the new archive.php, users can now run the archive.php script every hour using a webcron, ie. calling http://server/piwik/misc/cron/archive.php?token_auth=SUPER_USER_TOKEN_AUTH_HERE
This is quite cool for users who can't setup cron jobs on limited shared hosting. We should update the Cron doc