Lent are the 40 days (excluding Sundays) from Ash Wednesday to Easter Saturday. For Christians, they are a reminder of the 40 days Jesus spent fasting in the desert after his baptism. Traditionally, you'd give up meat and eggs during that time (hence the tradition to hunt for Easter eggs after lent) - the modern version is to give up something that you feel is holding you back or affecting you negatively. And you don’t need to be Christian to do that.