How about the German two-year notes, at an average yield of minus 0.06%, meaning it will pay back less money in two years than it received from investors. Meaning the buyers-investors in the notes won't get any interest payments and will actually get back less money than they put in 2 years later.
I know a few who have mortages for less tha 3%. But someone paying you to use their money. I'll take a few thousand at that rate.