Sounds just like roulette or coin flip disguised as something else.
I think you are referring to Binary Options and most have 60 seconds expiry time. There are a few like FortuneJack or Secondstrade. Search the forum for those. But they are risky.
i heard there ia like 50% chanse to win
intead of binary option, i find more fun and i like much trading forex. You can take a look at the site 1broker, that offer deposit/whitdraw in bitcoin. Remember that your coins are at risk in these platform, play responsabilly.
Does for ex trading involve skill ? Its not just pure luck is it ? You can increase your odds through understanding the market right ?