I want to suggest you somethings which actually help you get some profits with bitcoins by investing. Try to trade with bitcoins price, try trading with altcoins, try to invest in HYIP and if none works invest some money in gambling site's bankroll.
All other suggestions are good but investing in HYIP is never recommended, because that is a reason why a lot of people are regretting of losing their bitcoins now a days, HYIP sites are never good for investments, someone should rather try something else than wasting the money on a HYIP.
LOL! Investing in scams? HYIP's are scam and yes it is not recommended by me either. Much better if you will just let your bitcoins grow on your wallet.
Because HYIP's are never been safe investments, don't get fall for their sweet words that you will get ROI very fast and you will get high hourly interest.
Don't donate your bitcoins to them.
If any business model gives or offers unrealistic profits then surely they are scam programs. No way one can generate money 100% profit in a month or few days successfully in the longer run. If they know such methods then they won't come to public money . Instead they would have used their won money and take full profit. Those are just a scam programs.