colors on the training calendar

This may not be complete, but:

Green = Race Day
Pink = S, B, R info
Peach(?) = Sports or Strength info, but no S, B, R info.
Blue = You've entered information at the top, like hours slept, weight, etc.
Yellow = You've entered in comments for the day, but not much else.
White = Nothing!

Red Outline = At the top, you've adjusted the Injured/Sick information.
Grey Outline = Current Day

I tried to list them in order or precedence.  i.e., if you enter in S, B, R info and Strength info, the box with be pink.  Hopefully someone else will chime in if I've left something off or have inaccuracies.  BTW, I don't think there is a list somewhere, but I could be wrong on that.

Well done, Dave. Here's the official key: 

PINK = Run, bike or swim data.

PEACH/LIGHT RED = Strength data, with or without tri-sports.

BLUE = No Logged workouts, ONLY health data.

YELLOW = Only logged 'Overall Comments'

GREEN = Race Day

RED BORDER= Injured/Sick

GREY BORDER = Current day

This is from  the "Logging your Workouts " help article, section 6.