Someone here mentioned lending. So this is legit? So are you guaranteed you get the btc back? What is the minimum/maximum btc you could lend and how long? Example let say you have 1 btc you want to lend. So if you lend 1 btc for a month, how much btc would you get back? Do people lend a short time like a week or its usually at least a few months? So if someone lends 1 btc for 6 months, how much btc are they looking back to get? Most importantly, the other party can't just take your btc and not give it back to you right? Is it backed by the exchange? Well what happens if that person who borrows doesn't pay back exchange?
If you're using it with an exchange such as Poloniex, yes, unless Poloniex gets hacked, you will *generally speaking* always get your interest + lended amount back.
The lender will automatically get liquidated if his account exceeds the amount he needs to pay you back.
(Sometimes when the market is in a free-fall, he could be short a bit, since he probably won't be able to liquidate exactly right. but this is pretty rare, and i haven't seen it happen personally. Not that i've used Poloniex's margin trading features excessively, but hey.)
The interest on these services however is extremely low, + i wouldn't trust Poloniex.
Lending on the forum can be quite dangerous, as a lot of users will simply not pay you back and basically sell you their collateral, usually not for what it's actually worth.
I've always looked Argus-eyed at the Lending section, and still wonder how lucrative it really is.
Another option you have is investing in the bankroll of Cryptocurrency casino's. I haven't tried this myself, but it looks pretty ludicrous, which is making me very tempted to try this out in the near future.
See
https://bitcointalk.org/index.php?topic=2445163.msg46443989#msg46443989Might be something you want to look into.