Yes there is. In full page calendar view click on the vertical bar just to the left of "Monday". You can customise colours from the side bar menu that appears. (click on the down arrow to the right of the named activity)
@elseygirl: Try selecting a colour in the first row on the palette. I've just experimented a bit, and most selections from the remaining two rows (except the lightest grey #EAEAEA) won't stick and leave the colour unselected (thus “white” or clear) upon reloading the Calendar.
Is it still possible?After the hacking periode, i don't find it anymore....
This is not related to the Garmin outage. See this thread and respond there if you want to join the conversation: Category colors gone in Garmin Connect Web Calendar :-(