You can find the dates and locations here:
http://jw-media.org/index.html
2008/2009 "Guided by God's Spirit" District Conventions of Jehovah's Witnesses
Three-day conventions begin in the United States on the weekend of May 23-25 and will be subsequently held in cities throughout the world. The public is welcome to attend. Last year, more than 12 million people attended one of the more than 3,200 of such conventions that were held worldwide.
You can also get that information by writing the branch office of Jehovah's Witnesses in that country. To get the address of the branch office, go to www.watchtower.org
I think there is one at the Related Link.
The website JW-media.org does not list the dates for the convention in Hawaii, so you may be able to get that information from this source: http://www.jw-media.org/contact.htm
English * June 20-22 * June 27-29 Spanish * July 4-6 * July 11-13
You can contact the branch office of Jehovah's Witnesses in Thailand at this address: PO Box 7 Klongchan, Bangkok 10 240. They will be able to provide you with that information.
June 20-22 June 27-29 July 4-6
June 13-15 and June 20-22
Here is the wed link to the dates and times for the District Convention across the US: http://www.jw-media.org/newsroom/index.htm?content=/region/americas/usa/english/releases/events/usa_e080409.htm
Yes. As of the 2007 service report for Jehovah's Witnesses there were right at 200 witnesses and 3 congregations of Jehovah's Witnesses in Gambia. If you are in Gambia and you wish to find the nearest congregation to you, use this web addy ( https://watch002.securesites.net/contact/submit.htm ) to provide your contact info and within a few days or weeks, a witness from the area will contact you.
Most of the conventions are over. Here is the web address for the dates and sites for all the conventions in the US. : http://jw-media.org/frames/080409.htm Hopefully you will be able to find a convention that you can still attend.
The Henry Convention - 2008 was released on: USA: January 2008 (Slamdance Film Festival)
Fairport Convention Maidstone 1970 - 2008 was released on: USA: 19 February 2008
Jazz in the Diamond District - 2008 was released on: USA: 2008