Calendar allows you to set custom colors to your labels or categories, helping you to better recognize events. Once a category is set, the option to use labels is disabled until the categories are disabled again.
Choose from memorable keyword labels such as those listed here:
Categories are available as well and are the more up-to-date version tracking events. With these enabled, the Label control becomes disabled until all Categories are unselected.
Custom colors and labels can be chosen for either Categories or Labels by clicking once on an event, then selecting All Categories or All Labels from the Categories drop down menu on the ribbon.