The last day of Dhu’l-Hijjah is the last day in the Arabic calendar.
According to some narrations mentioned by Sayyid Ibn Tawus in his book of Iqbal al-A`mal, it is recommended to offer a two unit prayer on this day reciting Surah al-Fatihah once, and repeating each of Surah al-Tawhid and Ayah al-Kursi ten times each.
After accomplishment, it is recommended to say the following prayer:
اَللَّهُمَّ مَا عَمِلْتُ فِي هٰذِهِ ٱلسَّنَةِ
allahumma ma `amiltu fi hadhihi alssanati
O Allah, as for any act that I have done in this year
مِنْ عَمَلٍ نَهَيْتَنِي عَنْهُ وَلَمْ تَرْضَهُ
min `amalin nahaytani `anhu wa lam tardahu
but You have warned me against doing it and You have been displeased with it,
وَنَسِيتُهُ وَلَمْ تَنْسَهُ
wa nasituhu wa lam tansahu
I have forgotten it but You have not,