Sailing - Salcombe is big on sailing and boats can be hired from South Sands, amongst other places. South Sands and the Island Cruising Club, in Salcombe, offer sailing courses. The harbour is a great place to learn to sail as it is safe but with good winds and plenty of options for trips.
Surfing/Windsurfing - Bantham Beach, about 5 miles from Malborough, is considered one of the best beaches in Devon for surfing and wind surfing. http://extremesportsx.com/2012/02/26/five-of-the-best-beaches-for-surfers-in-devon-and-cornwall/
As with anywhere in the UK, the surfing is better during the winter than in the summer. Training courses are available from the Bantham Surfing Academy. (http://www.banthamsurfingacademy.co.uk)
Ride and Explore, Electric Bikes to hire, Salcombe Bike hire co 07877 526 297 www.letsgovelo.co.uk
MotorBoats - Motorboats can be hired from Salcombe and can be left at the town key. Several companies also offer training courses for driving the faster powerboats. (http://www.salcombepowerboats.co.uk/)