Or red.
Failing that there are some funds out there that are getting 20% returns in the last 6 months (I have a small/moderate amount invested)... but then again maybe the casino is a safer bet.
What you are really asking for is a 25% return on your money (turn $4 into $5). So it all depends if it's money you can afford to lose. There are no surefire bets that I know of. If 50% of your capital goes down the gurgler is that going to have a big impact? If you have another $20m to fall back on probably not.