You know, I like to climb trees and ride bikes and play.

Like a tracer running through the veins of the city, networks of air quality sensors attached to bikes can help measure an individual's exposure to pollution and draw a dynamic map of the urban air on a human scale, as in the case of the Copenhagen Wheel developed by new startup Superpedestrian.

Once I decided to retire from bikes, there was no thought to go racing again. I wanted to have a full year off and maybe even see the world a bit.

I love to go bungee jumping, jump out of planes, ride motorbikes, do kickboxing. I love all that stuff.

I do the same things I did when I was 12 years old: I ride bikes, I read books, I walk in the woods. And I listen to music.

I wouldn't recommend people to go up and ride their road bikes in Kenya. Bikes are not meant to be on the roads. But the mountain biking is fantastic. You can go right up into the tea and coffee plantations up in the highlands. You can descend the great Rift Valley.

I grew up in a culture of motorbikes. So I like racing just fine. Quite a lot, actually. That was when I was a boy in Australia. And I never really made the jump to cars after that.

I wanted to really just understand... how could a whole generation of children who were just children at the time - boys riding their bikes, flying kites, and doing all kinds of things they normally do - how could they suddenly be taught a completely different curriculum?

I'm not keen on cars and motorbikes. I tried to be a biker, but it wasn't me - I bought a Harley-Davidson and dumped it.

They were singing, Gillette, the best a man can get, with a lot of guys hugging their fathers and sailing and riding bikes. I suddenly felt a long way from the best a man could get and I thought it would be nice to get from there to the best.

I love mountain-biking or any form of bikes, like dirt bikes; I love getting out there, although obviously I have to be careful.

I am a bike enthusiast; there's a certain amount of romance to bikes. They're both beautiful and utilitarian.

I grew up north of Chicago, not far from where the Schwinn bicycle plant used to be, and was conscious of the fact that these beautiful, everlasting bikes were made just down the road.

Whenever I say I made a record in the garage, people just assume that I have, like, a Lear jet parked in there or something. But really there's old luggage, a couple of bikes. It's big enough to put one minivan in. That's it. No dartboard. I'm so not macho.

I cycled when I was at high school, then reconnected with bikes in New York in the late '70s. It was a good way of getting around the clubs and galleries of the Lower East Side and Soho.

I don't think people are going to switch over to bikes because it's good for them or because it's politically correct. They're going to do it because it gets them from A to B faster.

I was riding dirt bikes when I was a little kid. I got my first Harley Davidson when I was 17 years old. It was a frame with wheels and a tank on it and all the parts in a box.

It seemed romantic but also tragic - people would be winning but then lose it all, or crash but fight on, break bones but get back on their bikes and try to finish. Just getting to the end was seen as an achievement in itself.

Every summer in my old area, Bow, these kids from across the road used to bring out quad bikes in the park. They let me have a go, and I don't know what was wrong with me, but I drove straight into a gate and fractured my big toe. I had this mad limp for ages.

Yeah, Travis Scott's dad taught me how to ride minibikes and how to repair the engines. His name's Jack Webster. Jack had a drum set and his brother had a bass. So I used to play with them, and that's what started me wanting to get into music and take it serious. And this is before rap.

It was very much like Norman Rockwell: small town America. We walked to school or rode our bikes, stopped at the penny candy store on the way home from school, skated on the pond.

Mom and sister played piano growing up; my grandma still plays piano in church. They always beat me over the head trying to get me to play piano, but I was more interested in riding dirt bikes and playing in the mud.

Historically, the French have had a romantic attachment to their bikes. Though the first functioning two-wheeler is thought to have been invented by a German in 1817, it was the French who popularized and marketed the device in the 1860s, giving it the name 'bicycle.'

In Dogtown, skateboards are like bikes to the Chinese.

My friend Jonathan had a great tree house. It was awesome. It was like a big fort up in this tall magnolia tree... That's where we would conduct our very important business, I'm sure, with all our bikes leaning up against a tree and no girls allowed, handling all sorts of important things you handle when you're seven or eight.

Our home in Dubai is a beach house, so it's more casual and not formal in its tone. It's a holiday home. We are mostly in the pool or on the beach or in the sun. It's an outdoor place for the family. So there are mudbikes, a boat, football posts, and the pool is heated.

My father enlisted at the age of 17. He lied about his age because he wanted to ride the fastest motorbikes, which were with the British army.

At school I was a disaster, but when I would design, I could feel a sense of pride. I've always designed, and I would literally design everything I'd see: cars, bikes, motorcycles - everything.

People who race bikes don't talk about crashes. They keep going.

There's no more expensive sport than racing bloody motorbikes.

When I crash during a race and injure myself, what's the point in whinging? Because I put myself in that position. No one's making me race motorbikes - I want to go and race motorbikes. The most annoying thing for me is lying in hospital and not being able to get to work. I get beside myself.