You should probably figure out what your risk tolerance is. The more you stand to lose, the more you could win. What are you going to use this money for in 1-3 years? The traditional advice is either bonds or stocks, likely with some amount of diversification. Bonds are safer than stocks, but might not return as much. See this site [1] with a quick overview of some investment options of varying degrees of risk.

For what it's worth, it's probably not a bad idea to put it in the S&P 500[2]. In the long run, it's probably going to outperform most other investment strategies, although if the US economy tanks in the next few years you could lose a good bit of what you put in there.

I also think that allendoerfer's advice about investing in yourself can be very good, depending on your situation

[1]http://personalfinance.duke.edu/prepare-your-future/savings-...

[2]https://personal.vanguard.com/us/funds/snapshot?FundId=0040&...