I am MOH for the first time ever for my lovely, lovely friend. She's one of the first people in my social circle to get married so I don't have many comparisons for hen dos. About 20 people are invited (although don't expect all 20 will be able to make it), ages range from the bride's 18 year old sister to her 50-something future MIL. I am falling upon Mumsnet asking for your party planning wisdom. What makes a good hen do and what makes a bad hen do?