Hello, I've never taught about lent so don't have any resources or tried and tested lessons. That said, if I were introducing this as a topic I would start by connceting to what they may know something about - the preparation for a wedding. How do a couple prepare for a wedding? Obviously you have all of the practical preparations - venue, date, invitations, cake, food - but also the personal preparation - marriage preparation classes to prepare emotionally for marriage, and maybe going on a diet, doing exercise etc to look your very best for the day. You can then link this in with lent being preparation for believers to celebrate Holy Week. A time for reflection and getting themselves right with God. Some fast from certain foods or activities as preparation and a reminder of what is to come. Anyway - hope this may be of use.