A partial list of technology and other future claims that are not crazy

Living off the grid is not crazy. It costs about $23000 for a 2000 sf home

More on living off the grid

Solar power is not crazy.
Solar power is near a tipping point. It it gets to $1 per watt for installed panels it should takeoff without subsidies. Right now the best values are at about $3 per watt installed.

Update June 2006: Nanosolar building 100 million plant to make 400 MW per year of thin film solar cells

Wind power is already well on the way as cost competitive. 5% of UK power by 2010.
Update May 2006: More economical wind systems

It is not crazy that ordinary folk can afford in the future what only the rich can afford now. You can get a lot now relative to a wealthy person in the past.

In 1900, a wealthy man would have his own newspaper and printing presses. Now cheap blogs and high volume laser printers $300-1000. Higher end if you want color.

A wealthy guy could hire a maid. Now you can spend $200 for an iRobot broomba.

It is not crazy that personal manufacturing capability could become common.
A fab lab costs about $16000-20000 now

Laser cutters and the ability to make complex electronics etc…

Robots becoming very capable and common is not crazy.
The latest robot hobbyist status

Robot tech is advancing

It is not crazy that more people could afford jets and supersonic jets.
Business jets are coming down in price to around $1 to 2 million.

If you are actually pretty rich now, you can buy Migs and assemble an air force.

Something to point out from the Wired article. An L39 Soviet tactical jet fighter can be had for about $300,000. You just have to shop smart.

It would not be that expensive for someone motivated to put together a personal collection of unmanned flying vehicles and robotic security.

Getting into space is not crazy.
Suborbital flights coming for about $100K. Orbital flights to follow.
Update: potentially cheaper launch systems

Being rich in the future is not crazy.
The amount of wealthy people is growing at about 8% per year. Populations overall are growing at about 1% or less in most places. So if you are in a developed country and not becoming affluent then you are being left behind.
Updated wealth statics June 2006