The only requirement to join MENSA is a high IQ. Many of it's members are just regular people.

From their website:

There is simply no one prevailing characteristic of Mensa members other than high IQ...........Mensans range in age from 4 to 94, but most are between 20 and 60. In education they range from preschoolers to high school dropouts to people with multiple doctorates. There are Mensans on welfare and Mensans who are millionaires. As far as occupations, the range is staggering. Mensa has professors and truck drivers, scientists and firefighters, computer programmers and farmers, artists, military people, musicians, laborers, police officers, glassblowers--the diverse list goes on and on. There are famous Mensans and prize-winning Mensans, but there are many whose names you wouldn't know.Mensa Information