Every year, TED (my favorite conference) picks three extraordinary individuals who are dedicated to some worthy goal, and awards each $100,000 and a 'wish' which the TED community will then help fulfill. One of this year's winners is Jill Tarter, an astronomer and SETI's director for research, who had a worthy wish and gave a fantastic talk (embedded below, or click here). While SETI has been somewhat controversial, there is no doubt that finding extraterrestrial intelligence would be one of the greatest discoveries of all time, so the search, in my view, is justified despite the low short-term probability of success. (It's a low-probability high-yield investment, in other words -- not unlike projects to defend ourselves from asteroids, except in the latter case we're trying to avoid the high cost of a low-probability event).
See also: an interview with Tarter on the TED Blog and follow the progress on her wish at her TED blog.