According to the Wimbledon website (refer to the link, below), as of June 2009, the grass courts at Wimbledon are made of "100% Perennial Ryegrass".
At wimbledon the players play on the grass surface.
The seating capacity of Wimbledon's Centre Court is 15,000.
Yes, a retractable roof was added to the center court at Wimbledon in 2009.
The capacity of Wimbledon Centre Court at the time of the 2009 Championships is 15,000.
As of 2009, there is a retractable roof on the Wimbledon center court.
The Wimbledon trophy is made of sterling silver.
It is simply called "Centre Court"