Megablogging. No post can have fewer than 140,000 characters.

A photo-sharing app that gets $50M+ in VC and spends 500K on their primary domain.

No idea what it will be when he starts it, it almost doesn't matter - but by the time he is done it will probably be awesome.

Guys like Ev just need to start with something, they are adaptable enough to find what works. Put him in a room with a dozen people, $5M and let it simmer for a few years.

A couple years ago Ev wished there was a better calendar to-do list integration out there.

That was about three years ago, see http://www.economist.com/node/10328123

A web application which will combine a project manager, contact manager, and to-do list. It won't be named Pyra.