The fun factor - musical stairs. This video shows how people rarely used the stairs until the piano steps were installed. After installation, practically no one uses the escalator.
Demonstrates the power of a simple technological object to create a complex network powered by human intelligence and asynchronous interactions, & demonstrates people's willingness to engage (and empathize) with a "creature" that mirrors human characteristics of vulnerability, near helplessness, and being lost. Similar to (though it explores the themes from a different angle) Terrel Miedaner's short story "The Soul of the Mark III Beast" (anthropomorphism, empathy, etc.).
zips together like a honeycomb! Modular Decagon Tents by Logos: スペースベース デカゴン N600-J | OUTDOOR LOGOS：アウトドアロゴス
When the idea is invisible -- Dramatizing the new zero-emission technology, Mercedes literally made the car invisible to the environment through a pretty impressive cloaking effect. I love it because the idea is simple, well executed and effective.