If you want to enjoy the surroundings more profoundly, sleep under the stars, exposed to the elements, be your own master, at your leisure, and feel one with nature, you should definitely try camping!
Camping in Sri Lanka you can make several choices: do you want to go eco or not, do you want to stay in a national park or not, do you want your stay to have some luxury or are you looking for just the basics, do you want to stay at the coast or do you prefer the elevated, mountainous areas. There are options to cater to all of these choices.
Being out and about, you should consider the weather conditions in the different parts of the country over the course of the year. The best time of year for camping in most parts of Sri Lanka is roughly from February till June.
Temperatures are best, not a lot of rain, not too dry, and too hot yet. From July through September temperatures are rising and it is dry, so dry that streams and pools may dry up altogether, leaving less wildlife or water sports activities (think e.g. white water rafting) to enjoy. In the months October through January the monsoon causes showers of rain, that vary in volume and length. Generally speaking, it is wet during those months.