No. 255.

The longest Olympic marathon finishing time is fifty-four years, eight months, six days, thirty-two minutes and 20.3 seconds. The Japanese runner Shizo Kanakuri fell asleep after taking a break close to his nineteenth mile during the 1912 Stockholm games, then woke up the next day. He was invited back to complete it in 1976 when he was sixty-seven.

(Source: http://www.telegraph.co.uk/culture/qi/9472902/QI-Quite-interesting-facts-about-the-Olympics.html.)

No. 201.

Daniel Radcliffe, upon being presented with a picture of Elijah Wood to sign at a Japanese premiere, wrote 'I am not Elijah Wood. Love Daniel Radcliffe.'

(Source: The Graham Norton Show.)

No. 106.

When playing golf, the Japanese would rather not get a hole in one as tradition dictates that they should distribute the wealth, and send gifts to their friends and family.

(Source: The Unbelievable Truth.)

No. 38.

In Japan, the character Tintin is known as 'Tantan'. 'TinTin' is Japanese for 'penis'.

(Source: @qikipeida - the official Twitter feed of the QI elves/researchers.)