A few surprises (with more to come)
GanttPV

GanttPV - Project scheduling software

Good news for project managers! GanttPV, an open-source project scheduling tool, is now available for Windows and Mac OS X.

With GanttPV managers can define tasks, task durations, dependencies, start dates, and holidays. Based on this information GanttPV calculates task end dates and creates a gantt chart that can be used to communicate when project tasks should be completed.