I see that too.

My calendar is marked as blue (#0000FF) in evolution, but is shown as black in the clock applet. Interestingly, it is also shown as black in "Dates".

Even more strange, if I try to set the color to be blue in "Dates", it turns green in "Dates", evolution, and the clock applet. Similarly, red turns yellow, etc.

This looks like it might be a bug in evolution-data-server, or it might be some API call, where the color values have changed their meaning.

Versions used:
Ubuntu 7.04 (Gutsy)
gnome-panel     1:2.20.1-0ubuntu1
evolution-data-server   1.12.1-0ubuntu2
dates   0.4.3-1ubuntu2.1

In my case, one friend's calendar is set to display as #0000FF and another as #00FF00. The former displays as #000000 and the later as #0000FF. 

Sounds to me like evolution-data-server components might be shifting the bits around, for some reason.

Actually it's a bit of both.  the panel uses the deprecated e_source_get_color
call which doesn't handle all formats of the saved color correctly (See
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=477807 for a potential fix).. Instead it should use e_source_peek_color_spec

Created attachment 109908 [details] [review]
Use e_source_peek_color_spec and gdk_color_parse to get the appointment colors

I can confirm this bug on Ubuntu Hardy 8.04

This problem has been fixed in the development version. The fix will be available in the next major software release. Thank you for your bug report.

*** Bug 479753 has been marked as a duplicate of this bug. ***