Any ideas to show boss your appreciation?

I want to do something for my supervisor and DON to show them how much they are appreciated. We are having a lot of changes with our facility and our management is so good about sticking by us and helping us get through all these rough patches. They advocate for their nurses. They are some of the best management I have ever had and I want to do some kind of subtle gesture or card or something to show them our appreciation.

I would like to do something more than just an email. I have a few ideas of my own but still deciding. Has anyone done anything like this before? National bosses day is October 16 so I have plenty of time. Any thoughts/ ideas would be appreciated!
I initiated a group donation for a gift card to a very nice local restaurant.Quite an effort, garnered $300 . The manager kissed HER manager's patooti and insisted on sharing it.They both wrote me up for BS 2 months later.Save yourself the grief. Management is for management.... don't let them fool you.