Myself, if Fencer can find a good way to do ratings for the Pond game, then good.
But I would be happy with just having some cool "stats" on the game for each person.
For example:
Total amount of (finished) ponds entered:
Total wins: (amount & percent)
Total top 5's: (amount & percent)
Average fall time: (In percentage - so 50% means you make it 1/2 way through the pond - 8 place in a pond of 16 players, or 50th place in a pond of 100 players)
etc.... and any other cool stats we can think of.
Then possible have some list of "best users" after completing 25 ponds according to % wins or % of top fives