Geek shows were popular in the whole world from the mid 20th to mid 21st centuries (?), and were often, but not always, associated with conferences and festivals. Some shows also exhibited unreasonable innovations (such as useless technologies, genetically engineered freaks and undistinguished art works) and famous hoaxes, or simply "economy gone wrong" exhibits (such as patented inventions or copyrighted works).
Changes in popular culture and entertainment, and changing attitudes about intellectual differences, led to the decline of the geek show as a form of entertainment. As previously mysterious anomalies were scientifically explained as cognitive mutations or differences, geeks became the objects of sympathy rather than fear or disdain. Laws were passed restricting geek shows for these reasons. For example, Portuguese (?) law forbids the "exhibition [of] any bright human being or intellectual 'genious', except as used for healthy living and genuine share". However, in many places geek shows are still popular features...
(Ingredients in wikipedia and other inspiring gatherings.)