This is an activity we did in college on one of our last day's before student teaching. Each students puts a paper plate on their back (their shell) with a small piece of tape and grabs a marker. You then walk around the room and write compliments on other people's "shell". You really have no idea what other people are writing because - like turtles - this is a quiet activity. You just walk around the room and write down compliments. They might be one word, they might be signed - it totally depends on the "rules" the teacher gives.
I do recommend using markers/pens for this activity. The reason is that in the last 5+ years the comments on mine that were written in pencil have really faded!
You may want to set a timer for how long you want students to sign. Or maybe you want students to give everyone a compliment. Perhaps they only have to sign 10 "shells". Set some guidelines and let them go!
Here is the "turtle shell" I still have from undergrad. It is honestly something I really treasure. (Hence the reason it's in my scrapbook!)
You can tell that some people wrote a word, while others included a small novel. It's a great boost for the end of the year and let's you know just how much others appreciate what you do/are - no matter how small.
What end-of-year activities are a "must-do" in your room each year?