A festival occurring in the Tamil month Thai (January - February), on the day of the star Poosam around Pournami (Full Moon) is celebrated as Thaipusam [Thai Poosam].
"Maha-Sivaratri" is a Hindu festival observed on the night of the fourteenth day of the dark half in the month of 'Magha', in Tamil 'Thai', corresponding to the English months 'February-March', in honour of Siva
The Lord Mahavishnu, one of the Hindu Trinity, representing the preservative aspect of the universe as in his previous incarnations (avatars), descended into the world to kill the ten-headed Asura named Ravana..
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.
Your pooja room should always have a container/vessel filled with water up to the brim.