Remember, this is a made-up scenario to test how this might look during election night
To make sense of any of this you must understand the Electoral College
Red states are states that went for Bush in 2004
Blue states are states that went for Kerry in 2004
States against a blue background at the top have been called for Obama
States against a red background at the bottom have been called for McCain
States inbetween have not been called.
States to the left of the line have gone to Obama or are projected to go for Obama
States to the right of the line have gone to McCain or are projected to go for McCain
The further left or right they extend, the further the (projected) margin of victory
The wider a state is, the more electoral votes it has.
The numbers inbetween states near the finish line mark how far that boundary is from the finish line.
The projected winner is the person who takes the state on the finish line.
Once the area for states called for one person or another crosses the finish line, the election as a whole can be called for them.
Each state also carries a code such as "CA (55) 18%", which means that CA (California) has 55 electoral votes and is projected to go for Obama by a margin of 18%.
I know the red/blue state thing caused a lot of confusion but it's dead important to the pol junkies, so I've just put it right at the top of the explanation! It also makes the chart prettier - more colourful :-)