It's a wonderful activity to do with children, gets them out in the fresh air whilst learning about where their food comes from. I positively encourage Matilda to learn about fresh produce and to help me in the kitchen. Since I've been allowing her to help make dinner, stirring the pot and mixing she's eaten all her food up.
We went to Medley Manor Farm in Oxford but you can use this very aptly named website pickyourown to search for the nearest farm to you. We were told that raspberries, blackcurrants and redcurrants will be ready within the next couple of weeks as will beetroot and broad beans. So take an afternoon and go fruit picking.