The month being Aani and Aadi, the monsoon months in India in general and in Southern India in particular, there are not many important festivals in July. The festival season begins with the advent of Shravana in the month of August. However there are some important days observed in the month of Karkitakam/Aadi.
17th July 2009 - Karkitaka Sankranthi
Devi Bhagavathi is worshipped specially in the month of Karkitakam and the pooja starts on this day. The house and surroundings are given a good cleaning and Devi is installed in a special peetham in the pooja room
21st July 2009
This is considered a special day to propitiate the pitrus and pitru tarpana is given to the deceased especially by the side of holy rivers.
31st July 2009 - Varamahalakshmi Pooja
This is a special pooja performed by women to propitiate Devi Bhagavathi for the well being of the family and a long and happy married life. This the pooja is not performed in our family and hence I am not aware of all the rituals connected with the pooja.
Have a healthy Karkitakam!