In this modern era of GM strength computers, faster time controls and rapidplay finishes, it's sometimes easy to forget that the traditional way to finish a long game was to "adjourn" and play the game to a finish at a later date.
The great Russian masters would use this to their advantage by helping their compatriots with adjournment analysis against foreign opponents. One of my favourite anecdotes concerns such an adjournment. Mikhail Botvinnik and Paul Keres were helping to analyse Efim Geller's (pictured) game against Olafsson at Wijk Aan Zee in 1969. Botvinnik found a plan which involved bringing the King to e1 and then offering a sacrifice of the exchange that would enable Geller to win, but unfortunately it could be prevented. Botvinnik's advice to Geller was clear:
This plan would be successful: Firstly his opponent would not expect it, and would not think to prevent it in time...Also the white King would be retracing its steps and Olafsson would be hoping for the position to be repeated three times and would not want to change the position himself...Finally, rock about in your chair several times, as many players do in a vain attempt to find a plan!
Soon after the resumption of play, Geller was in a winning position. When asked what had happened, Geller simply smiled, "I rocked about!".
(This makes me feel a little better about my own case of gamesmanship).
I also recall an amusing little poem about an adjourned game:
A chessplayer travelled to finish a game;
he was sure he was going to win.
He talked all the way of the moves he would play,
and the knight which his rook would soon pin.
He continued to boast and became so engrossed
that he drove past a sign which said "Halt!",
and St.Peter's first words when he got to the gates were,
"Bad luck lad, you lost by default!"
(the Botvinnik anecdote is taken from the book "The Psychology of Chess" by Hartston and Wason).