I have had a pot luck in the past.
I also have written down each staff members name and then had staff randomly draw a name. They then have to write a one to two sentences about this person on paper and give it back to me that day. It needs to be something nice. After a 10 day worth of what co-workers said, I typed up the things that were written on nice paper, omitted the staff persons name that wrote the sentences, rolled them up and tied with a ribbon and little charm (can find in craft store for like 50 cents a piece). We then presented them to each person as a gift. It is nice to get the kudos from co-workers.
Some common things:
I like Jane Doe because she always helps out when asked.
I like Jane Doe because her garbage is always empty when I come to work.
If an employee does not like the persons name they drew they still had to say something nice...One said I like Jane Doe's eyes...blue is my favorite color.