LHC@home

Well, that's what happens on all projects. But it's not "wasting", since you don't know which of the results will come first (and thus which are being wasted). Also, if only one is sent, they won't know if it's correct. If two are sent, and aren't equal results, one of them is bad (but which?). If three are sent, two match and one doesn't, there is the answer.

You wouldn't have read Minority Report, by any chance? :D