I have a doubt : Does "Every second saturday" is useful ?
Right now, it can only mark "the second saturday of each month".
(eg. 2013 12 jan, 9 feb, 9 mar, etc)
I don't understand, does it meaning that some people only on leave at the second saturday of each month ?

I think, if change it to mark "the saturday of every other week" will be better.
(eg. 2013 12 jan, 26 jan, 9 feb, 23 feb, etc. In other words, interval 14 days.)

Specific practices can be (example of use lua):

-- First, setting a variable "is_need_offset", let peoples to select if needs.
-- (it's already exist, Options - Advanced - "Week number delta")

is_other_week = math.floor(math.fmod(os.time()/(86400*7)+is_need_offset*7, 2))
nowWeekday = os.date("%w")
if nowWeekday == "6" and is_other_week == 0 then
-- To Mark Today --
end

Thanks.

Added :
Suggest, at event/task recurrence dialog add similar option.

I personally do not use !

And I agree with your proposal...

And why not have several colors for the days of the weekend...

anoob wrote:
I have a doubt : Does "Every second saturday" is useful ?
Right now, it can only mark "the second saturday of each month".
(eg. 2013 12 jan, 9 feb, 9 mar, etc)
I don't understand, does it meaning that some people only on leave at the second saturday of each month ?

The second saturday of each month is holiday in India (or so I was told). The setting was added as part of custom work I did for a client and decided to leave it to the official Rainlendar version too.