The next Preston Guild will be 2012. Same year as the London Olympics. Since 1179 a guild fair has been run in Preston and since 1542 every 20 years except for 1942 which was moved to 1952, the year after the Festival of Britain in London. So not really similar then.
The guild was originally to promote the traders of the town, a sort of business union, and was run by Burgesses as an official body. Now the guild is a celebration of the town, now city, businesses who set up tableaux on the back of large vehicles which parade through the city during Guild week.
The Guild has spawned many things, for example, the phrase 'every Preston Guild' meaning something that doesn't happen very often. There is a Fuschia called Preston Guild. A quick look on the internet will find guild medals dating to 1700's, there are also songs, beer and books. Prestons main Theatre and Concert Hall is in the Guild Hall.
One of the best websites I've found on the subject is the Guild Collectables.
Preston, Lancashire, England.