Introduction

(1) 13th, 14th and 15th of Rajab, Shaban and Ramzan are known as "Ayyam-e-Bayz" - (the days of surpassing splendour)  

(2) Imam Jafar Sadiq(a.s.) has said "whoso prays during the nights of Ayyam-e-Bayz infact stands at the door of super abundant favours, bounties and benefits available in these months".  

(3) It is highly desirable to observe fast on 13th, 14th and 15th and have a bath every day and give alms in the way of Allah(swt).  

(4) In the nights of "Ayyam-e-Bayz" pray 12 Rakat namaz as under: -
- In the night of 13th, pray 2 Rakat:  In each rakat recite Sura-e-Fatiha, Sura-e-Yaseen and Suar-e-Mulk.
- In the night of 14th, pray 4 Rakat in 2 sets of 2 rakat each exactly as above.
- In the night of 15th, pray 6 Rakat in 3 sets of 2 rakat each exactly as above.  

(5) In the night of 15th, recite Ziarat of Imam Hussain(a.s.).  

Pray the following 12 Rakat Namaz in 6 sets of 2 rakat each: -

in every Rakat recite
Sura Fatiha - 4 times
Sura Ikhlas - 4 times
Sura al-Falaq - 4 times
Sura al-Kafiroon - 4 times
Sura an-Naas - 4 times
Sura al-Qadr - 4 times
Ayatul Kursi - 4 times
Tasbeehat-e-Arbaa - 4 times (Subhan Allahe, wal hamdolillahe, wa la ilaha il allahu, walla hu Akbar)  

After each salam recite 4 times:
ALLAHU ALLAHU RABBEE LAA USHRIKU BIHEE SHAY-AN
WA LAA ATTAKHIDU MIN DOONIHEE WALIYYAA
WA MAA SHH-ALLAAHU LAA QUWWATA ILLA BILLAHIL ALIYIL AZEEM  

In addition to the above, aamal of Umm-e-Dawood are also performed on the 15th day of Rajab.
Infact, they can be performed on the 15th of any islamic month.
The full details of Aamal Umm-e-Dawood are available in the book "Mafatihul Jinnan" and "The Prayers Almanac" which are both available online at http://www.shiamasjid.com.