(support ended in 2014).
Search for "Microsoft Office 2003 Lite 72 MB" on archive.org, major abandonware databases, or legacy forums like MSFN or WinCert. Look for file names such as:
For users on dial-up connections (still common in parts of the world) or those reviving old hardware (Pentium III/IV, 256 MB RAM, Windows 98/XP), every megabyte counts. A 72 MB download is manageable even on a 2 Mbps connection; a 2 GB Office 365 installer is not.