Make musicals of the following:

Lagaan
Lady Gaga songs
Phantom of the Paradise
Nightmare before Christmas
Labyrinth
Ziggy Stardust and the Spiders from Mars
Yoshimi Battles the Pink Robots
Dark Side of the Moon
Abbey Road and/or Magical Mystery Tour
Brooklyn is Love
We Are Pilots
Who Killed Amanda Palmer
Blood Moon

Environmentalist social network

Website that let's you easily track how much you're harming the environment with your carbon footprint or whatever, and brands will offer prizes to whoever keeps their footprint the lowest.

Street cellphone chargers

Make cellphone-charging "towers" of some sort where people pay to (lock up? and) charge their phones on street corners, or perhaps in delis

"World peace" website

<p dir=ltr>Start a website where people just project their ideas on finding world peace, and/or ask for help needed.&#160; With a way to weed out the&#160;irrelevant off-topic&#160;comments.&#160; A&#160;more public google group type site with active monitors?&#160; </p>
<p dir=ltr>We all want&#160;world peace&#160;(well, most of us, anyway)-- the internet allows for unprecedented info-sharing and collaboration that might actually allow us to do it-- what are we waiting for???</p>
<p dir=ltr>Let's get google, Facebook, craigslist, and apple "on it" to make this social networking site just for helping people and asking for help</p>

Teach children to teach themselves

Schools should explicitly empower children how to explore and learn about what THEY want to learn.  A class (or afterschool proram perhaps? just something.) on how to understand what interests you.

Along the lines of the google business model of 20% time dedicated to personal interests-type deal.

School can be soul-crushingly rigid and I can't imagine that's the way to get children excited about learning anything.