Complex sentence: OpenOffice.org (OOo), commonly known as OpenOffice, is an open-source office suite, derived from the open-sourced version of StarOffice, which Sun Microsystems acquired in 1999 for internal use.
Split into simpler sentences: OpenOffice.org (OOo), commonly known as OpenOffice, was an open-source office suite. It was an open-sourced version of the earlier StarOffice, which Sun Microsystems acquired in 1999 for internal use.