Ruffs were usually made of linen. If the wearer was rich, the ruff would be made partially or entirely of lace. They began to become popular in the 1560's gradually growing in size through the 1570's to the 1580's. In the 1590's some women had ruffs that were open in the front - connecting from the edge of the square neckline in front, going around the back of the neck to the other side of the square neckline. These were worn with a supportase (a wire or buckram frame in back to hold up the ruff).
The linen or lace ruffs were starched and the pleats were set using a hot metal poker.
Rowan Atkinson (as Black Adder) described Percy as looking like "a bird that had swallowed a plate" when he made an appearance in an extra wide ruff.
Here's a link on how to starch a ruff: http://www.faucet.net/costume/period/ruff.html
Ruff is a period card game for two pairs involving tricks, that resembles whist. Each player is dealt seven cards. The top card of the remaining three defines what suit is trumps. Whoever has the highest card in trumps picks up the three cards and discards any three, face down. Then play for ordinary tricks. There is no bidding and no wildcards. Stormholders like to play ruff!!! (needs the rules to be finished)
An eagle's ruff are the lengthened feathers that stand out on its neck. This is one way to discriminate between eagles and falcons in heraldry. Also, in falconry a bird is "ruffing" if it strikes its prey but does not seize and immobilise it.