I LOVE formal nights. Now that we have discovered cruising, my fun thing to do is to see how little I can pay for a long formal gown on sale. Ha! I'm starting to get a fun collection and even though my husband could CERTAINLY do with nothing more that a pair of shorts and T-shirts the whole trip, he knows how much it means to mean that we are both dressed to the hilt on formal nights. It gives me a chance to keep telling him how handsome he looks and I think he likes that part. We bought him his own tux for about $125 and he's worn it so many times that we're getting a kick out of the use.
In January, we're taking all 4 kids on a cruise (VOS) They range in age from 19-27. I told the older boys about formal nights and they were excited about it too. The conservative son has a dark navy 3-pc suit that he will most likely wear. The other son dresses quite...different. They don't have tuxes, but the 2nd one tends to be more "creative" in his fashion so I suggested that he get to some thrift stores and start looking for some fun creative formal wear. He really liked that idea.
I think that "formal night" really is trying to tell people that the night should be something special. I love seeing everyone joining in the fun. This certainly isn't everyone's "thing", but those are probably the people who would ultimately get the most out of it in a fresh new way if they would just go with the flow for a night. Make it fun!