Hello Namratha, Sri Lanka is a beautiful country and offers much to explore. There is a long list of offbeat things to do in Sri Lanka. I'd like to share my personal favourites with you. Chug up on the slow blue train that runs between Kandy to Ella. This train offers scenic ride views of tea plantations, intersecting streams, pristine waterfalls, pine forests and mountain tunnels. Visit Galkadawala, which is a small countryside village and Sri Lanka's best-kept secret. This place is a forest lodge with an oasis by the village lake, made up of recycled material. You can spot colourful birds in the mini-forest and savour delicious meals with home-grown veggies.
Do not miss out on enjoying Sri Lanka's rich culinary awesomeness. Try out hoppers with its endless forms, some served with potato curry and coconut sambol. Pol Rotti, Yeast Rotti, Kothu, curries and rice are enough reasons to visit Sri Lanka over again.
Trincomalee, popularly known as Trinco has Sri Lanka's most beautiful beaches - Nilaveli and Uppuveli. This place is located on the east coast and you can spot dolphins and blue whales here. It is a great spot for diving and yet untouched by a flock of travellers.
Hope this helps you to enjoy, just like I did!