A kickstarter clone, that could be implemented in a few lines of code on top of Ethereum..
If there is > 1,000 Ether in this contract address before timestamp x then send the Ether to the project lead, else refund all the users.
If there is > 1,000 Ether in this contract address before timestamp x then send the Ether to the project lead, else refund all the users.
And they can include conditions about arbitrary information that is reported on the blockchain (weather data, stock prices, etc...)
And multiple people can sign these things. They really are like contracts.