There are lot many interesting things to do in Gangtok, you will enjoying doing the whole day.
Sight-Seeing: Gangtok is one of the very few hill stations in India that is not crowded to the hilt and you can enjoy extended moments of pure bliss. Gangtok sightseeing offers panoramic views of the Himalayas, especially from Tashi Viewpoint.
Though you will be charmed by Gangtok”s serenity, for energetic moments make a trip to the famous Pemayangtse Monastery to see its priceless antiques and idols, and to the nearby ruins of Rabdantse, the 17th century capital of Sikkim. Also visit the 200-year-old Enchey Monastery.
If you want to see the Chogyal’s Palace, visit Gangtok in the last week of December when the palace is thrown open to the public for the Pong Labsal festival and see the masked dancers perform to the mighty Kanchenjunga. The masks depict various Gods, demons and dragons and if you want to decorate your room with some of these brightly coloured masks, you can buy them from the souvenir shops.
Enhance your knowledge on Tibet with a visit to the Research Institute of Tibetology. The institute houses some rare manuscripts, books as well as priceless artifacts. You can also visit some of the other monasteries and stupas in the city itself. The Do-Drul Chorten is one of the most important stupas in Sikkim and is encircled by 108 prayer wheels. Rotate the wheels and ask for a wish and maybe the Enlightened One will fulfill your prayer. Like most hill stations, Gangtok also has its share of some rare orchids that bloom all through the year. The Orchid Sanctuary houses over 200 species of rare orchids and is a treat.
Shopping: Go shopping in Gangtok for masks, footwear, carpets, handicrafts and other trinkets in the souvenir shops strewn along Mahatma Gandhi Marg. The main shopping areas in Gangtok are the Old market, New market and Lal market. Also look out for the traditional items like thangkas or religious scrolls and choktsees or collapsible wooden tables with intricate local Tibetan designs. Sikkin tea with its exotic taste and aroma is without a doubt a must bring back home.
Outdoor Activities: The outdoor activities in Gangtok include short treks to the nearby hills and if you are a seasoned player, you can go treks that last for more than a week and will take you through some very tough but exceedingly beautiful routes.