A comprehensive TeX system that you can install on your hard disk. It includes support for most Unix architectures, including GNU/Linux and and for Windows. The MacTeX is developed as part of the the TeX live effort, and has similar properties, but is distributed separately.

The TeX, PDFeTeX, XeTeX and LuaTeX engines are provided in the distribution, with several different running formats each.

Beware: the download is large (>1Gbyte); it comes in the form of a ISO image for a DVD, lzma-compressed.

See also texlive-source.

The author is The TeX-live team.