Why would you do that? It seems like a big risk to put a stack of money outside your wallet in some gambling site that may dissapear next morning.
Unless someone has a better idea to make profit off those 40 BTC, I would just hold them. The interest is the what you will get as BTC goes up in price in the future.
If you want quicker rewards you need bigger risks, and that's probably trading, gambling and putting your coins in some dodgy place like BTCJams or a house edge on a casino.