Complex sentence: The 2006--07 ISU Grand Prix of Figure Skating was a series of international invitational competitions in the first half of the 2006--07 figure skating season.
Split into simpler sentences: The 2006--2007 ISU Grand Prix of Figure Skating was the ISU Grand Prix of Figure Skating series of the 2006--2007 season. It was a series of international invitational competitions in the first half of the figure skating season.