Bitcoin and Alt Coins (other crypto coins).
There is little doubt that crypto currency is here to stay, the question being how it will evolve, which coins will survive and of those which will be the leaders with real value.
Bitcoin is the original blockchain and coin developed by Satoshi Nakamoto in 2008.
Since then other coins have emerged (and many failed already). There are currently in excess of 1500 coins being traded however the vast majority are scams or ponzi schemes. My best estimate based on research is that about 50-60 of these currencies are legitimate.
With scam coins and ponzi schemes, many people have made significant returns by riding the wave of optimism of a new coin and then selling out fast. Once the sell off occurs everyone else is left with a worthless coin.
Find a list of coins and their values by visiting this page.