Ready, set, paddle! Paddle, swim, run, and bike across Charleston's barrier islands in this year's ECOthon, sponsored by Barrier Island Eco Tours. This course is designed to challenge your physical ability while being fully immersed in the nature of the Lowcountry. All the funds raised for the event benefit the Charleston Tibetan Society, improving the lives of Tibetans around the world, as well as the Lance Armstrong Foundation, assisting and inspiring people affected by cancer. Isle of Palms Marina, 50 41st Ave Unit A, Isle of Palms. Sunday, all day. $90-$80. www.ecothon.org