FreeBSD and OpenBSD provide a ports collection using Makefiles as the scripts. NetBSD provides a similar collection called pkgsrc. These automate the download of the source code from the Internet, the creation of an "object code" page from the source code, and the installation of this object code to the computer so that users can start playing.
Using OpenBSD 3.8 as an example, a user might build the Battle for Wesnoth game from source by using these commands:
$ cd /usr/ports/games/wesnoth $ make SUDO=sudo install
The developers of OpenBSD 3.8 used similar commands to build a
wesnoth-0.8.11.tgz package which users can download from OpenBSD and install without using the ports collection.