I have seen 280slides.com and it is really impresive. But its developers had to create their own language.
Which platform or language would you use to have an as similar as possible functionality? Is it possible to do something similar in python? Could you give any working examples?
From memory, that language (Objective-J) compiles into javascript, so it's just the old HTML + CSS + Javascript + <insert server-side language here>. Python could easily be the server-side language. If you want examples of python web frameworks, look at Django and Plone.
Inventing our own language was a miniscule part of the problem. What was important was developing the right framework, which is now available as Cappuccino (cappuccino.org).
You ask what platform/language you could use to develop something similar? I assume you already know that the answer to what platform is the web. 280 Slides is web based, and that is an integral part of the experience.
And when it comes to the web, you realistically have one development choice: JavaScript. Fortunately, once you accept that, there are a lot of things you can do, including targeting JavaScript with other languages (like Java with GWT).
Objective-J is a pretty thin layer on top of JavaScript, so if it's the only thing keeping you from trying Cappuccino, I strongly recommend giving it a shot. As far as the server is concerned, there's nothing remarkable going on. Almost all the magic is happening in the browser.