Timeboxing

So I’ve just read about another way to get tasks done similar to GTD, but it’s mostly used in software development.

A definition that Wikipedia gives “Timeboxing is a planning technique common in planning projects (typically for software development), where the schedule is divided into a number of separate time periods (timeboxes, normally two to six weeks long), with each part having its own deliverables, deadline and budget. Timeboxing is a core aspect of rapid application development (RAD) software development processes such as dynamic systems development method (DSDM) and agile software development.”

What methods do you use for project management?