I'm sure it will sound silly, but I never knew you could still castle if your rook was under attack.  Just found it out today by accident.

yep, also, on the queenside, your rook can move over a square that is being attacked.  Sometimes in puzzles you do this to win a rook on b2 by castling with check. 

sweet! Thats nice to know. It would be nice to be able to castle in check sometimes.

The only time you can castle when your king is being attacked is when you have previously bribed the arbiter.

sstteevveenn wrote:

yep, also, on the queenside, your rook can move over a square that is being attacked.  Sometimes in puzzles you do this to win a rook on b2 by castling with check. 

You are correct, here are the rules of casting:

Castling

Under certain, special rules, a king and rook can move simultaneously in a castling move.

The following conditions must be met:

• The king that makes the castling move has not yet moved in the game.
• The rook that makes the castling move has not yet moved in the game.
• The king is not in check.
• The king does not move over a square that is attacked by an enemy piece during the castling move, i.e., when castling, there may not be an enemy piece that can move (in case of pawns: by diagonal movement) to a square that is moved over by the king.
• The king does not move to a square that is attacked by an enemy piece during the castling move, i.e., you may not castle and end the move with the king in check.
• All squares between the rook and king before the castling move are empty.
• The King and rook must occupy the same rank (or row).

When castling, the king moves two squares towards the rook, and the rook moves over the king to the next square, i.e., black's king on e8 and rook on a8 move to: king c8, rook d8 (long castling), white's king on e1 and rook on h1 move to: king g1, rook

Another version:

Castling is permissible only if all of the following conditions hold: (Schiller 2001:19)

1. The king must never have moved;
2. The chosen rook must never have moved;
3. There must be no pieces between the king and the chosen rook;
4. The king must not currently be in check.
5. The king must not pass through a square that is under attack by enemy pieces.
6. The king must not end up in check (true of any legal move).
7. The king and the chosen rook must be on the same rank.^[2]

It is a common mistake to think that the requirements for castling are even more stringent than the above. To clarify:

1. The king may have been in check previously, as long as it isn't in check at the time of castling.
2. The rook involved in castling may be under attack.
3. The rook involved in castling may move over an attacked square (a situation possible only with queenside castling

And finally a link:

http://chess.about.com/od/beginners/ss/ble14cas.htm

trust this is helpful, any questions just post on the forum.

eternal21 wrote:

I'm sure it will sound silly, but I never knew you could still castle if your rook was under attack.  Just found it out today by accident.

Apparently, one time at a high-profile tournament Victor Kortchonoi stunned everyone by asking the arbiter if he was allowed to do this!

Viktor Korchnoi beat Karpov in a game after castling with his rook under attack.

http://www.chessgames.com/perl/chessgame?gid=1067831

Whatever Karpov's plan was apparently fell apart after Korchnoi castled as he resigned while his game still had some life left in it. 

one more rule I could think of, is that the King must move first, then the Rook or both of them at the same time.

Thanks for the posting... especially sstteevveenn''ss posted position!