 There is a Hasidic custom of omitting Tachanun the entire week of Purim (11-17 Adar) and the entire week of Lag BaOmer (14-20 Iyar).Some communities omit Tachanun on 7 Adar because it is the anniversary of the death of Moses.Additionally some Hasidic congregations omit Tachanun on Friday mornings (getting ready for Shabbat), and some even on Sunday mornings (revival from Shabbat).