Suggestion for carnival float theme?

Question

We are a group of 16 year olds, (male and female) it'll most likely be a walking entry with about 30 people. Any suggestions for an interesting theme? Must be quite easy to do but effective? What have you done in the past that works?

Answer 1

Synchronised swimmers.  The people round the edge can hold a sheet of blue material with a slot in it and the people in costumes in the middle can appear from it, hide underneath it then poke through fake legs.