Examples:

<b>Nanotubes</b>

Nanotubes are a material currently produced only in research
quantities. They are too expensive and take too long to produce
presently to be practical. However, their day is coming.

Nanotubes allow for the creation of materials that are 1,000 times
stronger than steel, and electrical charges can cause strands to bend.

A net could be made of nanotubes and stretched over the spectator
areas. The extremely durable nature of nanotubes would allow for the
spectators to pull and tug on the net without realistically damaging
the net.

A ball hit into the stands would normally be a home run. With the
net, the ball would roll back into the outfield and the spectators
could significantly influence the roll of the ball. If the
outfielder catches the ball, it's an out. So if the spectators want,
they can make the ball much harder to catch or even make it roll foul.


<b>RFID</b>

RFID or Radio Frequency IDentification tags are about the size of a
grain of rice. They store digital data that can transpond with a
remote transciever up to about 600 feet away. The same RFID can
communicate with many transcievers.

An RFID embedded in the glove of each player and each baseball would
allow for a computer to render a layer over a TV image showing
exactly where each player is, for a given player where they should be
playing based on computer statistics (batter tends to hit right field
and short, player on first & being able to accurately throw to
second, ...). So as spectators are watching, live data streams next
to players to provide greater insight into what is happening.

Ball speed, predicted trajectory, and anticipated player interactions
would be displayed and instant replays would show the differences
between the computer predictions and what actually took place.

When a ball is hit, a computer can read the ball position and
estimate which seat the ball will hit within the first 100 feet of
being hit. An automated message could come over the loudspeakers
estimating which chair the ball is going to hit. "'Upper deck, seat
K21' And Davis hits a long one into right field." This would happen
long before a human announcer could even judge where the ball might
go.