For those who do not know what Time Zone they are in take a look at this image:
http://upload.wikimedia.org/wikipedia/commons/3/3d/Timezones_optimized.png
thanks to Wikipedia! if you are on 56k or lower it might take time to load sense it is a large image and it is PNG

Some example from Wikipedia!

The definition for time zones can be written in short form as UTC±n (or GMT±n), where n is the offset in hours. Here are
some examples:

San Francisco, California, USA: UTC-8 (e.g. if it is 12:00 UTC, then it is 04:00 in San Francisco)
Toronto, Ontario, Canada: UTC-5 (e.g. if it is 12:00 UTC, then it is 07:00 in Toronto)
Stockholm, Sweden: UTC+1 (e.g. if it is 12:00 UTC, then it is 13:00 in Stockholm)
Cape Town, South Africa: UTC+2 (e.g. if it is 12:00 UTC, then it is 14:00 in Cape Town)
Mumbai, India: UTC+5:30 (e.g. if it is 12:00 UTC, then it is 17:30 in Mumbai)
Tokyo, Japan: UTC+9 (e.g. if it is 12:00 UTC, then it is 21:00 in Tokyo)
Where the adjustment for time zones results in a time at the other side of midnight from UTC, then the date at the location is one day later or earlier. Some examples:

Cairo, Egypt: UTC+2 (e.g. if it is 23:00 UTC on Monday, then the time in Cairo is 01:00, Tuesday)
Wellington, New Zealand: UTC+12 (e.g. if it is 21:00 UTC on Monday, then the time in Wellington is 09:00, Tuesday)
New York City, USA: UTC-5 (e.g. if it is 02:00 UTC on Tuesday, then the time in NY is 21:00, Monday)
Honolulu, Hawaii, USA: UTC-10 (e.g. if it is 06:00 UTC on Tuesday, then the time in Honolulu is 20:00, Monday)
The time zone adjustment for a specific location may vary due to the use of daylight saving time. For example New Zealand, which is usually UTC+12, observes a one-hour daylight saving time adjustment during the southern hemisphere summer, resulting in a local time of UTC+13.

Source: http://en.wikipedia.org/wiki/Time_zones

Do not have to be as detailed as them just like to know when to plan this role-play "if" enough people is intrested

-Cricket Korta'Ari-