WikiSuite is the most comprehensive and integrated Free/Libre/Open Source enterprise software suite. It covers most of the needs most organizations have.
Yet, there are always software needs that are "Long tail". And thus, for which there are not a lot of suppliers. Or needs that are unique to each organization. Or sometimes, the available off-the-shelf software is not quite right, and you get in the buy vs build software debate.
In WikiSuite, we use http://tikitrackers.org/ which permits to address very specific needs, while avoiding custom code and avoiding spreadsheet problems. It's just advanced configuration which is managed via wiki pages. This is known as end-user development or No-code development platforms.