Many people has missed Bitcoin boat. Is bitcoin the end of the world ? I don't think so...
I believe in the near future there will be atleast 4 to 5 alternate currencies that will come close to the Bitcoin. So let's not miss these new boats !!

I am not an Economist. Following are speculations based on the info I gathered from different tech sources. This is an on going effort and I will be revising this list based on my findings. If you find this information helpful, don't forget to donate some BTC . No trolling please !! If you believe in anyother innovative alt currencies, feel free to share in comments.

Top 10 list:

1. Ethereum - https://ethereum.org/  ( Whitepaper - https://github.com/ethereum/wiki/wiki/White-Paper , Yellow Paper - http://gavwood.com/Paper.pdf )
    Ether Sale Dates: Start - 22nd July 2014 - End : 2nd September , 2014

2. Slockit DAO- https://slock.it/ ( Whitepaper : https://download.slock.it/public/DAO/WhitePaper.pdf )
    DAO Token Sale Dates : Yet to be announced

3. Digix Gold- https://dgx.io/ (Whitepaper : https://dgx.io/whitepaper.pdf )
    DigixDAO Token Sale Dates : Start - 30th March 2016 - End : 28th April 2016 (Ended in 12 hours as 5.5M cap was reached)

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Disclaimer : Some of these may end up as scams, So do your own research before investing your hard earned money.