Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

When you think of the People's Liberation Army, you probably don't think of line dancing. But the Chinese military's latest online recruiting video makes a soldier's life look more fun than the macarena. The brief spot, posted last week on the website of the Ministry of National Defense and going viral, features tanks and fighter jets, as well as soldiers dancing in rows to a quirky hit tune by the Chopsticks Brothers called “Little Apple”. Its lyrics include, “You are my little dear little apple/I can never stop loving you”.

If you’re afraid of heights, caves, the dark, suffer from claustrophobia or vertigo, this might not be for you, but if not, a small Welsh town has the perfect subterranean adventure for you: the world’s largest underground trampoline. Just unveiled in Blaenau Ffestiniog, North Wales, Bounce Below is a network of trampolines and slides mounted to the walls of an abandoned slate mine at heights of 20 feet to 180 feet off the ground. Visitors are welcome to climb, bounce, slide, and jump in the netting amidst a technicolor light show.

“Himalayan Dog”. This dog just appeared out of nowhere and followed us for an entire week during our trekking trip in the Himalayan outback. He always used to sleep in front of our tent and guarded us in the nights. When I decided to get up at 4 a.m. to climb the next 5000 m peak for sunrise he accompanied me as well. On the top he was sitting for the entire 30 minutes on this place looking straight into the countryside. Photo location: Ladakh, India. (Photo and caption by Sebastian Wahlhuetter/National Geographic Photo Contest)

A prototype Rollkers transportation device is displayed during a press event at the Mandalay Bay Convention Center for the 2015 International CES on January 4, 2015 in Las Vegas, Nevada. The product is not a skate; it balances for you and when you place it on the bottom of your shoe, it gives you the ability for faster transportation based on walking. The balance CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to about 150,000 attendees. (Photo by Ethan Miller/Getty Images)

Wang Zeyu, 4, a fee-paying enthusiast of kung fu, practises during a training class at a kung fu school near the Shaolin Temple April 10, 2005 in Dengfeng, Henan Province, China. Zeyu's father sent him to the school from his home in Jiangsu Province, thousands kilometres away from Dengfeng, when he was just 3 years old. And his father must pay 9,800 yuan (US$1195) for one year's tuition at the school, a huge amount for most Chinese. There are more than 80 kung fu schools that line the road from the city of Dengfeng to the Shaolin Temple with hundreds and thousands of young kung-fu lovers from all over the country and beyond studying here. All the schools use the Shaolin name to attract students as the Shaolin Temple is the birthplace of Chinese Kung Fu. (Photo by Cancan Chu/Getty Images)