Microblogging has made blogging quick and easy. No longer do you need to write up an elaborate blog post. Just a sentence or two would do. Tweets are also quick and easy to read.
Why not adapt this idea to programming? For example, you could allow twitter users to write python programs that fit in 140 characters.
Such programs would execute in your twitter reader by default, sandboxed and with a time limit. This would be particularly compelling if you have access to a graphics library and can create cool patterns in your tweets.
People can learn what these programs do by example and adapt them for their own tweets.
You couldn't "tweet" code because tweeting has a longer response latency than a REPL; you're waiting for a human twiteratus douchebag to write back or acknowledge your existence. But the repl makes up her mind in an instant, so you're hooked in a far more enjoyable, not to mention far more enlightening dialog than you could ever have on twitter.
Try it:
telnet prompt.franz.com 23
(look, an odd-ball question deserves and odd-ball answer, alright)