Med studies pay maybe 1.5 or 2 grand, but that might take 2 weeks. Throw in every kinda donation you can do (blood, plasma, sperm, bone marrow) and you might add another grand on it. Gives ya 2.5 to 3 grand in around 2 weeks.
But 5? Not legally. Unless you have some assets such as a car or whatnot to take a loan out against.
Buy (acquire) something and sell it. Artwork comes to mind - draw something, sign it, frame it nice, affix expensive price tag, figure out where idiots go to buy expensive art and sell the thing.
Do you know cars? Got an eye for something collectible that some old geezer is selling as a used car? What else do you know really well? I found a collectible guitar once at a garage sale. It was worth a couple hundred, but you might get lucky.
Sell something really stupid on e-bay. My neighbor kids sold genuine autumn leaves, nicely sealed in a ziplok bag. Actually sold a few. If you got some buzz going, you could do well. Grains of sand?