It's Dussera and Diwali time. Just got curious to know more about the same. DUSSERA celebrates the victory of Good over Evil. The nine days preceding Dussera are known as Navaratri. During this period, Goddess Durga is worshipped in different forms - as Saraswati, Lakshmi, and Mahakali(3 main forms of SHAKTI). Each of these 3 forms gave rise to 3 more forms and hence they are called Nava Durga.

NAVADURGA FORMS:
Shailputri Brahmacharini Chandraghanta Kushmanda Skandamata Kaatyayani Kaalratri Mahagauri Siddhidatri

You can know more about each of these forms from this link and even this too.

Nava Durga Stuthihi(Prayer/Song) :
Pradhamaa Shailaputricha; Dwithiya Brahmacharini, Thruthiyaa Chandraghantethi Kushmandethi Chathurdhikee; Panchamaa Skandamaathethi; Shashtaa Kaatyayanethicha; Sapthamaa Kaalarathreecha; Ashtamaachaathi Bhairavee; Navamaa Sarvasiddhischaath; Navadurgaa Prakeerthithaa !!!

Dussera also means "cutting the ten heads of Ravana". The ten heads represent:
Loathing, Desire, Envy, Selfishness, Dishonesty, Obsession, Gluttony, Rage, Passion, Pride.

And, DIWALI is called the "festival of lights". Diwali is celebrated for five continuous days and each day has its significance.
The first day of Diwali is Dhanatrayodashi. During Dhanatrayodashi, lamps are lit to welcome Lakshmi. Houses are decorated and homemade sweets are offered to the Goddess.
On the second day, known as Narakachaturdashi, the victory of Lord Krishna over the evil King Narakasura is celebrated. Few lamps are lit and few crackers are burst in joy.
The third day is almost exclusively devoted to the goddess, Lakshmi. Lakshmi Pooja is done. Lamps are lit and crackers are burst in joy.
Padwa is the name commonly given to the fourth day of Diwali. It is considered an auspicious day for starting new business ventures.
On the final day of Diwali, also known as Bhai-duj, the focus is on the love felt between brothers and sisters. Gifts are exchanged and food is shared.
You can check for some more info here.