(41CX/DM41)(17Bii) Date of the first Advent Sunday in a year

[Werner]

If you use 12.12 instead of 25.12, and change the 21 to 8, it will work for M.DY format as well.
[update] not quite.. but if you use 12.12, then do 13 DAYS+, then proceed as before, it will ;-)
[update #2] and if you take the first of January of the next year (which is always the same Day of Week as Christmas), it's even simpler:

Code:

 1
 +
 1E6
 /
 1.01
 +
 ENTER
 DOW
 +/-
 7
 MOD
 35
 -
 DATE+

Cheers, Werner