1. Mountain Biking, Cambodia
Mountain biking in Cambodia can be a rough and dusty experience, but imagine rolling through Siem Reap and the ancient Angkor temples, navigating the dirt roads by bike. You can also try different (and longer) routes that can take you as far as Poi Pet in the north, or even across the border to Laos or Vietnam.
Many agencies offer package mountain biking tours through Cambodia, some lasting for as long as two weeks, with hotel stays, chow, and a guide included in the package. Forget about taking a racer through Cambodia, the roads are simply too bad to permit it - take a touring bike or a mountain bike instead.
2. Whitewater Rafting, Cagayan de Oro, Philippines
Whitewater rafting in the Philippines is a growth industry, but you can't go wrong by going to the first. Cagayan de Oro River is studded with more than twenty rapids from class I to VI, and rafting companies offer beginner trips with rapids of no more than class III.
A number of professional rafting companies with trained guides are ready to take you rafting, providing state-of-the-art rafts, flotation devices, rafting helmets, and dry bags for your stuff - they'll even pick you up from the airport to take you to the jumping-off point! Expect to pay about $15-20 to take a beginner's course.
3. Surfing, Bali, Indonesia
Bali has been a surfing hotspot since the early 20th century, and continues to attract surfers from all over, mainly from Australia (due to the island's proximity to the southern continent).
Everyone's welcome to surf in Bali, though; the island's small size and unique geography provides a wealth of surfing conditions, in all seasons, for surfers of any level of experience. Newbies might like to try Kuta's kind waves, while more able surfers will want to Nusa Dua's shallow, sharp reef bottom and powerful, huge right-hand waves.
Tubing in Vang Vieng is extreme on the other end of the scale - this most laid-back of activities in the most laid-back of Lao towns is an adventure in sloth, once you wrestle that tube onto the river and get on.
You can rent a tire inner tube at many areas in Vang Vieng for about $4 the whole day. You can take a tuktuk out of Vang Vieng about two miles upstream, where you can enter the river with your tube and chill out for the next four hours, watching the incredible landscape pass you by, before the tube takes you back to town.
The river flows extremely slowly in the dry season, so you plod with the current until you reach the endpoint at Vang Vieng.
5. Base jumping in Kuala Lumpur, Malaysia
BASE Jumping is skydiving from a platform fixed to the earth - like the Menara Kuala Lumpur, with a viewing platform about 300 meters up, which is superbly suited to this thrillingly dangerous activity.
It's now a spectator sport in Malaysia more than an actual tourist activity, although tourists are free to climb onto the platform from which BASE jumpers launch, with cables attached to their persons.
The government has made BASE Jumping a competitive sport; in 2008, The Kuala Lumpur International Base Jump Merdeka Circuit 2008 made the circuit of six buildings across Malaysia, featuring fifty base jumpers from all over the world.