the UI i'm thinking of is

!wager <description> $<amount> @bettee MM/DD/YY

would trigger fletcher:

ok! If <description> on MM/DD/YY, @<sender> will pay @bettee $<amount> 
or donate it to a charity of @bettee's choice

Then on mm/dd/yy a reminder goes out, pinging both sender and bettee.

Maybe a two-step trigger that requires confirmation, because people will constantly forget the order of arguments in the API. (obviously a !wager --help message of some kind).

-- Quinn Dougherty Logician