Have a field day
Meanings
Fig: to go all out; to have it entirely one's way
Examples
Tabloids have a field day with juicy gossip about the rich -and-famous 
La stampa scandalistica va a nozze con i pettegolezzi sulle persone ricche e famoseSome American TV talk-shows have a field day with the dregs and the rejects of society as they expose their tales of woe and misfortune on the air. After all, the audience seems to like it!
Per certi talk-show della TV americana, le tragiche storie di miseria e sfortuna di poveri disgraziati, rifiuti della società umana, sono un invito a nozze. Dopo tutto, sembra che al pubblico piacciano molto!Origin
In the late 19th century, schools, clubs, companies, etc. began to have "field days", where people would indulge in hearty outdoor sports and drills just for the fun of it