Ganesh Chaturthi is one of the most popular Hindu festivals. This is the birthday of Lord Ganesha. It is the day most sacred to Lord Ganesha and it falls on the 4th day of the bright fortnight of the Tamil month Aavani (August-September).
Kerala's most colourful festival, Onam celebrates the mythical King Mahabali and his golden rule. It welcomes the spirit of King Mahabali, and assures him that his people are happy and wish him well.
The dark fortnight of Aswayuja (September-October) is known as the Mahalaya Paksha or the fortnight specially sacred for offering oblations to the departed ancestors. The last day of this period, the new moon day, is considered as the most important day in the year for performing obsequies and rites.
In the pooja room do not place pictures of Gods along with pictures of departed souls like grandfathers, great grandfathers etc. You can place them in the pooja room on a different side. For eg., if Gods are placed facing east you can place the pictures of the deceased facing south or north etc., If you worship this way then the blessings you will receive will be several fold.
You should always begin a Hanuman Pooja on a day when the star is Moolam and you should offer pooja only in the mornings.