1989, Perth, Australia. Netherlands plays Germany (in those days still West-Germany) in the semi final of the Women's World Teams Championship (contesting the Venice Cup). The German women are in the lead and show self confidence. Nothing can go wrong, so it seems.
But then the following board hits the table. It will turn out to be crucial for the result of this semi final.

S/-		♠	-
		♥	Q 10 8 7 5 4 2
		♦	A 10 7 6
		♣	10 3
♠	K 9 8 5 2			♠	A Q 10 7
♥	6			♥	J
♦	9 8 3			♦	K J
♣	A 8 6 2			♣	K Q 9 7 5 4
		♠	J 6 4 3
		♥	A K 9 3
		♦	Q 5 4 2
		♣	J

Marijke van der Pas must have thought it was her birthday. She doubled the 3♥-opener for take-out; a moment later the opponents bid 4♣ in her six card suit and stayed there after the double (for penalties) from Van der Pas' partner!
West, Elly Schippers, who could not dream of what had happened of course, did not find the best lead, trumps. After that lead and continued best defence, South would have made one (!) trick.
After Schippers' spade lead, declarer was able to ruff two spades in dummy and score the two red aces, meaning she was 'only' down six: -1400 to NS and 15 IMP to Netherlands. (At the other table the German women in EW were allowed to play in 4♠, scoring +450. Would EW have bid 5♠ over 5♥...? They were advised to do so, because 5♥ makes!).
Not only did this deal give Netherlands a huge profit, the mood at the table completely changed as well. Whereas Germany until then seemed to be impregnable and Netherlands offered a token resistance only, the match took on a whole different turn. Everything the Dutch women did, now turned into gold and Germany lost the semi final without standing a chance.

In her book I love this game Sabine Auken explains the misunderstanding. It occurred as follows: North's 3♥-opener showed a weak hand with a seven card suit in either hearts or clubs! NS had agreed that if South now would bid 4♣, this would be 'convertible'. Meaning: North would have to correct to 4♥ with hearts as her long suit and pass with clubs. South thus wanted to raise to 4♥ if North's suit was hearts and if North had clubs, it would have to end in 4♣ (compare this with a 2♠-response on partner's Multi 2♦-opener).
Alas, Von Arnim-Auken had not discussed how to react after a double. At the table Auken assumed the meaning of 4♣ would not be affected by the double. However, Von Arnim thought South now promised a club suit. Of course in turn South now assumed her partner held a long club suit, since the latter passed the double... So that is the way to end up in a 2-1 fit, doubled.