I'm sure you're familiar with the concept of the X-prize. The original usage of the phrase was in 1996, when $10 million was offered to whatever non-government entity could first build a reusable manned spacecraft and get it into space (defined as at least 100 km above the Earth's surface) twice within two weeks. In 2004, the prize was claimed by Scaled Composites and their project Tier One. Mike Melvill was the pilot of the first flight; Brian Binnie made the second flight. The two, as a result, became the first- and so far only- people ever to receive astronaut wings from the FAA as a result of a commercial flight.
The term 'X prize' has since been used to refer to any similar practice of putting up a cash prize for the first person to develop a desired technology, particularly those made by the X-Prize Foundation. For example, currently, another $10 million is being offered to the first person to bring them a tricorder. If you don't know what a tricorder is, that's the thing doctors use on Star Trek to figure out what's wrong with you.
Considerably further down the list of priorities, but no less important to the average person, is robocalls. Namely, how to stop them when the Do Not Call list can't or won't. So they put $50,000 up for the person who came up with the best idea as to how to stop auto-dialing telemarketers. The competition just wrapped up.
They got 798 entries. A lot of them involved Captcha. Three won; two shared the cash prize because the third winner came from Google. The technical aspects are only viewable by the judges, but we're able to see that:
*The first, called Nomorobo (which proved to be a very popular name for people's submissions), has calls go to both the phone and an intermediary database. If the calls are detected to be robocalls, the database answers the phone and immediately hangs up. If not, the database steps aside and lets the phone ring.
*The second sorts out phone numbers into a whitelist, blacklist and greylist.
*Google's idea basically involves crowdsourcing a spam filter that phones could refer to before they ring.
A lot of the submissions were rather more vindictive. Many involve sending robocalls back to the robocallers. At least one involved giving a telemarketer a blast from a fog horn. Another involved pressing a sequence of buttons on the phone to add $1 to the caller's phone bill (yeah, that would never be abused at all). Another involved people at a call center posing as consumers and making purchases to create a paper trail to prosecute with.
And then there was the man who suggested "block all calls- not a joke".
On the bright side, we could just text.