Alan Cameron shares some of his favourite urban interventions that bring out the youth in him.

On any given day Cape Town offers a lot of space for children of all ages to play. The beautiful Company's Garden, and the pedestrian streets of St George's Mall and the Fan Walk – which together make up the City Walk – certainly leap to mind.

While official attention is given to making cities more efficient, human interaction in public space is underpinned by the element of play. Everyone has experienced it before: playing equalises the field. It's suddenly not about where you come from or how expensive your toys are, but if you can keep the game in the air.

This level playing field encourages conversations and builds the community spirit while discouraging foul play. For this reason many cities look to reuse built infrastructure to start conversations and have people share the collective ownership of public space. Playing in the CBD isn't a new idea, and many cities have a lot of fun invigorating public space.

Here are some of my personal favourites.

1. Shadowing

As a person walks through the street light, their shadow is recorded and played back for the next person to walk through in that same space. Shadowing was implemented in Bristol, as the 2014 winner of the Playful City Award designated by social enterprise Watershed. "In its most poetic form it creates pools of memory on the street, essentially compressing time in a single space," explains designer Jonothan Chomko.

2. Hello Lamp Post

When last did you have an SMS conversation with a post box, or a bus stop for that matter? In 2013 Hello Lamp Post animated infrastructure in the Bristol city centre by allowing pedestrians to SMS the code found on the object to wake it up, and initiate a fictional conversation. Sometimes being annoyed after getting wet in the rain or pleased to see you, after a chat, the object would always invite you back the next day to discover more.

3. Playing Mannenberg

'Run a stick along these pipes to play Mannenberg' says the inscription. And, if you do, the opening tune of the anthem of the anti-apartheid movement rings clear as a bell. The memorial was created by Mark O'Donovan and Francois Venter and installed in 2004 as part of The Sunday Times newspaper Heritage Project to celebrate the people and events that made history.

Read about the concept of the installation, and about the legacy of the song. Photo by Lisa Burnell.

4. Yellow-framed Cape Town

Thought up by designer Porky Hefer and the Table Mountain Aerial Cableway these yellow frames look onto the iconic Table Mountain from a variety of vantage points throughout Cape Town.

Click on the link and submit your photo and be featured in the Be in the frame with Table Mountain gallery. Photo courtesy of Table Mountain Aerial Cableway.

5. Play Me, I'm Yours

What would happen if you plonked a piano down in a public space, with the words "play me, I'm yours" painted on? In short, pedestrians would sit down and start to play. The music started in 2008 and the idea hasn't piped down, with cities continuing to ask Street Pianos if they could be next to host the musical installations. As an added plus, the pianos are then donated to local charities and community groups.

Would you like to bring Street Piano's to Cape Town? Please do.

The Arts Centre Melbourne put together this video after inviting Street Piano's to come and play.

6. Turning a street into a supertube

Can you imagine creating a supertube down Waterkant Street? Luke Jarram, who also thought up Street Piano, helped turn Park Street in Bristol into a giant water slide.

If you're keen to bring this to your neighbourhood, a comprehensive instruction manual has been created to help spread the cheer. In exchange, a small administration fee and a donation to the Frank Water charity is requested. Contact [email protected] to receive the DIY manual.

7. Piano stairs

Can we get more people to take the stairs by making it fun to do? This question posed by Thefuntheory.com, sponsored by Volkswagen, was answered by piano music, again.

The answer is of course, yes.

More novel urban ideas from this smart crowd include a speed camera lottery where drivers obeying the speed limit stand a chance to win speeding fine revenue and an interactive glass recycling drum that encourages… yes, you guessed it – recycling.

• What are your favourite ideas to stimulate playing in cities? Leave your comments, and links too please, below.