What is a rally really like?

So I have been looking into rallies, I think they would be really good for our 6 year old, my wife has her own business so if often busy at the weekends so might be fun for me and him and they seem good fun. 

My question is what are they really like, we are not into the "package holiday organised fun" approach to holidays, we are not introverts and like meeting new people and families and love it when Elliott is off playing with other kids, I am just worried if we will find them overbearing. We saw a documentary online during the week about a rally with a tongue in cheek attitude to caravanning and it was all singalongs, party games and no sign of any restbite and made to look rather horrid.

So we are in Essex and would love to hear some real stories about what we should expect and any suggestions.