Honestly not sure how long this will last, but could be fun for a little while. Spacemining has been operational for 14 days and they are offering 100 GH/s for free just for signing up. What do you have to lose, right? Just follow https://www.spacemining.io/?ref=127931 to get your free 100 GH/s. I did the free signup and immediately saw that my account balance was going up, so I decided what the heck and deposited $65. This got me 6500 GH/s of bitcoin mining power, that was activated as soon as I had 6 confirmations on my transactions. I think it took about 3 hours. Their claim is that you will have ROI in 10 days. Well, I have been mining for 36 hours and have already taken 2 successful withdrawals to my Coinbase account for around $15 USD. Here is to hoping this site lasts at least 8 more days. LOL.