Surely start on a Monday and end on a Friday. Nope, unfortunately it is not as easy as that!
Never end on a Friday is a good maxim, well not unless it takes all weekend to deploy. Why not end on a Friday then it give us the entire weekend as a safety net if things go wrong?
But surely it is a good thing to start on a Monday though, it is the start of the week and everybody is nice and fresh, this means that we must end on a Friday. Well starting on a Monday is not a good thing either, for a few reasons.
So where does that leave us, ending an iteration on a Monday would be madness, too much is lost over the weekend and it would be risky. it also suffers from the same bank holiday problems as starting on a Monday. Ending on a Tuesday would probably be ok with the only disruption from bank holidays eating up a Monday. (Tell you what lets just ban bank holidays.) This leaves Wednesday as the best candidate for ending an iteration, and Thursday for starting back up again.
So now we throw things back into disarray again! there are times when Monday and Friday do make sense. Where you have short iterations of a week, the disruption caused by a weekend in the middle of the iteration is likely to be expensive. Here is would be better to have the disruption between iterations and end your iterations on the Friday, with a floating start on Monday of Tuesday.