best way is to take some new alt coin giveaway, if it will become popular, after few months you can trade it for some BTC. Seems most profitable giveaway was ripple giveaway. you could get 50k XRP and sell them at 10k XRP per 1BTC few months later. I have not participated it that giveaway, because i had no bitcointalk account at the time, but friend gave me some of his 50k XRP, and I traded them for 0.5BTC. So now I registered on this forum, to wait for next opportunity.