This hand occurred April 4, 2007, in club play. I opened 2NT, my partner bid Stayman and heard the amazing news that I had 4 spades, then asked Key-card Blackwood and found out I had all 4 of the missing controls. So he bid 7S. It turns out that my partner's bid is correct -- I usually will have two small hearts or the queen of hearts and the grand is either about 90% (requiring only to pick up the queen of spades) or 45% (also needed a finesse).
But this is the 20% of the time when I have 3 small hearts and there isn't a good chance for the slam.
There is not much to describe about the play. Obviously, in 6S, you find out trump at 2-1, then you give up a heart trick and claim.
Obviously, there is no point to playing 7S safe for down 1.
The opening lead was the queen of clubs. I had to assume the diamond king was onside, giving me 12 tricks on top. Then I needed to develop your 13th by a squeeze. Unfortunately, hearts is the only suit where I might have a threat against only one defender. Fortunately, I had threats in three suits.
So the play of the hand is to run the spades, at least until there is just one left; pay attention to the discards; try to figure out what is happening; then run the most likely double squeeze. At the table, Righty signalled positively in diamonds, which was good to see. Then Lefty abandoned diamonds while Righty abandoned clubs. No one pitched hearts, making it look like they were 3-3. So I ran the double-squeeze with hearts and the both suit. In fact Lefty had 4 hearts and was squeezed on the last diamond, for making 7.
But, because Lefty had four hearts, it was a true compound squeeze.