In August last year I used a website called Uniswap to swap some ICO tokens I had to Ether. Today I was reading a post about some guy who did the same and didn't realise because he had used the site he can claim 400 UNI tokens. 1 UNI is now worth $20. So I went on to Uniswap and linked the wallet I used on it all those months back. A message pops up saying "Claim your 400 UNI". So that's how I just made $8000. If any of you used the site before September 2020 you can also claim 400 UNI.