Goddess Durga Pandal in Bengal during Durga Puja, a Navratri Festival. -Wikipedia.org

Navratri, Navaratri, or Navarathri (Sanskrit and Hindi: नवरात्रि, Bengali: নবরাত্রি, Gujarātī: નવરાત્રી, Kannada:ನವರಾತ್ರಿ,Telugu :విజయ దశమి, Malayalam: നവരാത്രി, Marathi: नवरात्रि, Tamil: நவராத்திரி) is a Hindu festival of worship of Shakti and dance & festivities.
The word Navaratri literally means nine nights in Sanskrit, nava meaning nine and ratri meaning nights. During these nine nights and ten days, nine forms of Shakti/Devi are worshiped during these days.

Significance:

The beginning of spring and the beginning of autumn are two very important junctions of climatic and solar influence. These two periods are taken as sacred opportunities for the worship of the Divine Mother. The dates of the festival are determined according to the lunar calendar. Being the oldest religion in the world, Hinduism has numerous belief systems.

The Mysore Palace in Karnataka- Wikipedia.org

In Hinduism the adherents believe in one omnipresent Deity but may worship Her/Him in any of the numerous manifestations that are prevalent all over India. Navaratri represents celebration of Goddess Durga, the manifestation of Deity in form of Shakti [Energy or Power]. Dasahara, meaning ‘ten days’, becomes dussehra in popular parlance. The Navaratri festival or ‘nine day festival’ becomes ‘ten day festival’ with the addition of the last day, Vijayadashami which is its culmination. On all these ten days, the various forms of Mother Mahisasura-mardini (Durga) are worshipped with fervour and devotion.

Dandiya Raas:

The Dandiya Raas dance- Wikipedia.org

Raas or Dandiya Raas is the traditional folk dance form of Vrindavan, India, where it is performed depicting scenes of Holi, and lila of Krishna and Radha. Along with Garba, it is the featured dance of Navratri evenings in Western India.

Garba is performed before Aarti (worshipping ritual) as devotional performances in the honor of the Goddess, while Dandiya is performed after it, as a part of merriment. Men and women join in for Raas Dandiya, and also for the Garba. The circular movements of Dandiya Raas are much more complex than those of Garba. The origin of these dance performances or Raas is Krishna. Today, Raas is not only an important part of Navratri in Gujarat, but extends itself to other festivals related to harvest and crops as well. The Mers of Saurastra are noted to perform Raas with extreme energy and vigor.

For more info check out our Source : Navratri Wikipedia.org
Dandiya_Raas Wikipedia.org

From author’s personal experience:

Night dance gathering:

The Navratri festival in India plays are very important role of bring rare night festivity cultural amongst many people.
And this can be seen from the various Dandya, Garbhma cultural dance gathering which hosts from cultural to even a bit disco style of songs and music.

Visiting  Goddess Temples:

This is one of the biggest festivals in India even if it may be for 9 days along as during this time various people flock towards Temples of Goddess and some even perform various ritual from fasting-dieting to also not wearing anything on their feet’s and keeping them bare feet all this festival. But the one that surprised me the most was people walking bare feet for almost 1 day and 1 night towards the most famous Goddess Temple like Saptashrungi in Nasik, Maharashtra.
Its a pretty long walk and this great holiday is on top of 7 mountains. Being the 2nd largest tableland in Asia one cannot image the devotion that the people put towards this amazing power of believing in Gods. 
I even joined them one time to walk those 7 mountains at 4am in the morning and the view at first sunrise was simply breathtaking and when I finished the walks I did not even cut and cuts or bruises to my barefeets. Its simple amazing.

Well that’s all for now. Send us your experience during this great festival and spread the joy and happiness always.

Regards,
Anand Nav