Golden rectangle is AWESOME. It is essentially a rectangle based on the golden ratio. What is the golden ratio then? The golden ratio is a ratio discovered by Fibonacci (see Fibonacci Sequence). He noticed that a similar pattern emerged in nature, and this pattern is as follows:
1... 1... 2... 3... 5... 8... 13... 21... 34... and so on (this can go on for infinity, and all you have to do is add two adjacent numbers together to get the one to the right (ex: 1+1=2, 13+21=34) http://en.wikipedia.org/wiki/Fibonacci_number
So, the ratio comes from when you divide two adjacent numbers. You end up getting this ratio that they call the golden ratio or three to five ratio... (see 3... 5... in the sequence above). 3/5 = 0.6, 21/34=0.61 ... You'll find that all number you divide in this way (next to one another) will all equal about 0.6. THIS is the golden ratio. And, this is where the golden rectangle comes in. It is essentially a rectangle composed of this exact ratio.
"A distinctive feature of this shape is that when a square section is removed, the remainder is another golden rectangle; that is, with the same proportions as the first. Square removal can be repeated infinitely, in which case corresponding corners of the squares form an infinite sequence of points on the golden spiral, the unique logarithmic spiral with this property." http://en.wikipedia.org/wiki/Golden_rectangle
You'll notice that in nature, many shapes take this form, and it has been hypothesized that this shape is the most beautiful to the human eye. See what I mean, AWESOME.