Counting Only Specific Hours Between Two Times

What i need help with here is to find out how many hours (if any) are "Night hours" and/or "Weekend hours".
"Night" hours are from 21:00 to 06:00 any day.
"Weekend" hours are from Saturday 18:00 to Monday 06:00
It seems that the Total Hours part is working ok, i hope
But i just cant seem to find out how to get the Night and Weekend part to work
Iv looked high and low everywhere to try to find a salution to this, but just cant seem to find one
Iv attached a excel file incase that helps to understand what im looking for.

wow, that was just what i was looking for, thanks alot
iv tested it alittle now, and from what i can see, it had a few small "errors"
it looks like the "Night" calculations are working great so far. the only thing iv noticed there is that if "Start" and Finish" are left empty, it shows 6 hours in the "Night" section.
it would be great if it is left empty, or as 0 so i can add a automatic sum for amount of "Night" hours to it when its done.
on the "Weekend" part, it seemed to work on not counting monday to saturday 18:00, but when on saturday, no matter what time i enter as start time, it counts how many hours from 18:00 to "Finish" time. (if i enter 20:00 - 21:00, it still counts from 18:00 - 21:00)
and if "Start" and "Finish" are empty, "Weekend" shows #'s, but this is only on the line with Saturday.
also, if "Finished" does not have a time of 18:00 or higher, it also shows #'s on "Weekend" for Saturday.
on sunday, it looks like the "Weekend" does not end at 06:00 monday, it just keeps counting all the hours.

i have tried to do alittle fixing on this myself, but it seems it is alittle over my head atm to do by myself

oh, and i was thinking, it isnt really needed to check if the day is saturday or sunday, i was thinking i could just add the "Weekend" code to where there is a weekend.
that might make it alittle easier i hope

cool, thank you very much

thanks alot, again
iv hade a quick look at it now, it seems there are a few errors still
i dont want to bother you and take up more of your time, so ill see if i can understand how the code works and play around with it myself
thank you again very much, you have helped me out alot getting to what i wanted. 2 thumbs up

i thought id reuse this thread insted of starting a new one...
iv tried to play around with these codes, but i just cant seem to understand them or get them to work 100% the way i want
like i posted at the start of the thread, i need to be able to count specific hours on specific days, between specific times, if any.
i need to count the hours, if any, every day between 21:00 and 06:00 in one cell
and
i need to count the hours, if any, between saturday 18:00 and monday 06:00 in another cell

this is what i got so far:

column A is the day/date, formated dddd dd.mm.مممم (i have a norweigian windows Win XP Home SP3, and a english MS Office 2003, مممم=yyyy)
column B is the start time, formated tt:mm
column C is the end time, formated tt:mm
column D is the total hours between B and C, with the code: =IF(C3="";"";IF(B3>C3;C3+1-B3;C3-B3))
this seems to be working like i want it

column E is the total hours, if any, between 21:00 and 06:00, with the code: =IF(C3="";"";IF(C3<B3;MIN(C3;1/4)+(1-MAX(B3;7/8));IF(B3<1/4;MIN(1/4;C3)-B3;0)+IF(C3>7/8;C3-7/8;0)))
this seems to be working like i want it

now this is where i am having problems to get it to work 100%
column F is the total hours, if any, between saturday 18:00 til monday 06:00, with the code: =IF(C3="";"";IF(WEEKDAY(A3)=2;IF(C3<B3;MIN(C3;1/4)+(1-MAX(B3;7/8));IF(B3<1/4;MIN(1/4;C3)-B3;0)+IF(C3>7/8;C3-7/8;0));IF(WEEKDAY(A3)=1;IF(B3>C3;C3+1-B3;C3-B3);IF(WEEKDAY(A3)=7;IF(C3<B3;MIN(C3;1/4)+(1-MAX(B3;3/4));IF(B3<1/4;MIN(1/4;C3)-B3;0)+IF(C3>3/4;C3-3/4;0))))))

it seems that it does not count the hours right on monday and saturday atleast.
the start and end times, can be just about anything, so it has to work for all times, start and end.

if anyone has any salution to this it would be great, and if anyone could explain the codes in detail, that would also be great, id like to know how everything works, the help file didnt help me much

thanks for the reply
i tried the second code, both the first one, and the edited one, but i got an error on both as soon as i pressed enter after pasting the code in the cell.
after i pressed enter, and clicked ok on the error msg, it marked 2.5 automaticly, dont know if that ment that that is where it had a problem, but that seemed locigal atleast it marked 2.5 at the end of this:
=IF(C3="";"";MEDIAN(0;2.5-

and the formula for hours between 21:00 and 06:00 that i hade, seemed to be working, so i havent tested the one you posted. did you see/find any errors in the one i had?

thanks again for another test
i looked at your file, and from what i saw, i still got errors here. dont know if it is something with my version of windows or office, or just the language of both. im still getting errors on my file, it seems that the options i need are very hard to cover 100%
ill add i file to show what im working with, maybe that can help,
also got a new error, saying that "Negative dates or times are displayed as ########"
we work on every possible times, so we can start and finish at any time, with any time length, anything from 1 hour jobs to 16 or more hour jobs, even going from 1 day to the next. dont need to be able to calculate over 24 hours though