During every Shemoneh Esrei of mussaf, we pray that the Beis Hamikdash be rebuilt. However, only on Yom Tov do we mention that it was destroyed due to our sins - ומפני חטאינו. On Shabbos, and on Rosh ...
Possible Duplicate: Saying Ulichaporas Pasha in Musaf of Rosh Chodesh This question is a slightly different take on this one. I have posted a comment there and await to see if it needs to ...