I used this last trip and thought it was great, so am reposting it here for countdown! Just dont irk the FA by posting how many sleeps to go (I have too many to get excited just yet!):
To use Excel to calculate the number of sleeps to go:
In cell A1 type
=TODAY()
in cell A2 type
date that you are leaving eg 25/08/04
(those 2 cells must be formatted to "date" format)
in cell A3 type
=A2-A1
the result will be in number of days
(A3 cell must be formatted to "number" with no decimal places)