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When you stay in bed for so long that the time in bed exceeds the 'normal' sleep duration by approximately 9 hours and 18 minutes ( the duration of all three lord of the rings films without extended the editions).

It is also worth noting that an 'extended Lord of the Rings lie-in' exceeds 11 hours 20 minutes of 'normal' sleep time due to that being as long as the extended edition of the trilogy.
'Ahh Dave's having a Lord of the Rings lie-in after getting particularly messy last night'
by bisonman May 27, 2015
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