These are a few fun exercises to get people interact and have a laugh at the beginning or at the end of the class.
Everybody takes a noodle, tell them to form a circle, noodle behind their back under the armpits. They have to stand close enough to grab each neihboring noodle at the ends. When everyone is "connected" give them numbers alternating "1" and "2". Play music and tell the number 1's to float up to the middle while the number 2's start jogging in circle direction. For added fun let the number 1's splash as hard as they can with their feet.
After 2-3 rounds shout "Reverse" and let them jog the other way - which is hard as they have created quite a turbulence around them. Let them run for another 2-3 rounds and then switch the numbers.
3 person / 1 noodle. Numbers 1 and 3 at the ends, number 2 holds on tight in the middle with both hands. 1 and 3 jog clockwise (3 jogs in a big circle around, 1 is jogging on the spot) and drag number 2 along for a few rounds. Change direction and have them jog backwards (number 2's feet are floating in front now)
Make sure to change positions so that everyone has done every position at least once.
Have fun and thanks a lot for all your splendid ideas!