During the 98/99 season I saw a superb heads-gone from a player with the away side. His team were getting lashed about 7 or 8-0 (midweek game towards the end of the season, possibly a cup) and one of the Buffs fans was giving him and his team a fair bit of a slagging. This was right in front of the changing rooms area of the pitch.
Anyways the opposition player was taking a throw in and instead of throwing the ball and carrying on with the game he threw the ball and then proceeded to turn round and start swinging at the Buffs fan. Red card followed and I think the fan ended up following him into the changing room.