Here is an explanation of Nisfu Sha'ban's night and what worship should be done in this evening, such as tribun-timur.com reports from pesantrenvirtual.com:
With regard to the night of Nisfu (mid) Sha'ban there are several issues worth mentioning:
On the primacy of tonight, there are some traditions that some scholars believe are valid.
Among the Hadith A'ishah: "One night the Prophet prayed, then he prostrated long, so I thought that the Messenger of Allah had been taken, because suspicious then I move his finger and it was still moving.
After the Messenger after his prayer said: "O Aisha you can not part?". Then I replied: "No Messenger of Allah, I just think that no-no (think the Prophet has died) because you prostrate for so long". Then he asked: "Do you know what night it is today". "The Messenger of Allah knows better", I replied. "Tonight is Shiva's nisfu night, Allah watches his servant tonight, so He forgives those who ask forgiveness, gives their affection for love and removes those who are spiteful" (H.R. Baihaqi)
According to the narrator this hadith mursal (there is a rawi who did not connect to Sahabat), but quite strong.
In the hadith of Ali, the Messenger of Allah (saws) said: "The night of shah'ban nisfu, then live with prayer and be contented in the daytime, verily Allah descended to the heavens of the world that night, then Allah said:" Those who ask forgiveness will I forgive, rizqi will I give him rizqi, those who get the temptation then I release, until dawn. "(Narrated by Ibnu Majah with a weak sanad).