I've nearly been caught out twice when working with US based clients on dates. The US format for dates is month/day/year, whereas in the UK we use day/month/year.
Normally its not too much of a problem, but sometimes you just glance through and see that the first digit is a 9 for example and think, "OK it's the 8th today so they want to tomorrow".
In China they usually use year/month/day but often use the US format for English documentation. In HK they use the British format, and in Taiwan they use the US format or their own format.
The Taiwanese format starts with year 0 being the founding of the Republic of China (by Sun Yat-Sen). You have to subtract from the current year to get the Taiwanese year.
To solve the problem I always use the full written form for months "eg 2nd March 2006", and try to be extra careful when checking dates. Still I've almost been caught out twice.