rainy days
short term
long term
compound interest
speculation, gambling, market timing

There are several ways that promises to make money in the market over short periods and get hyped up every now and then:

market timing, for those that think they can foresee the direction a stock or the market is going to take next, a thing that has been proven impossible more times than anyone cares to remember, and to make matters worse trading cost are going to eat you alive.
day trading, the high "art" of buying and selling stocks within very short time period’s, which basically will also kill you off due to trading costs.
charting and technical analysis, looking at past trading prices, trying to see patterns that have been here before. As the markets a random this also is quite impossible
stock picking, buying single stocks that you think are well worth it. Unfortunately also a problem with the trading costs, as well as foregoing you chance to diversify away some of the risk associated with owning stocks.
fund manager picking, as you aren’t smart enough to beat the market, why not employ someone that might be a lot smarter then you? But no luck here either, and to make matters worse, now you have to pay the fund manager in addition to all the other costs.
hedge funds, take a basic fund with it's trigger happy fund manager, relieve him or her off any rules and regulations there might be, like actually specifying the sort of stock he or she is going to buy, and give them leave to buy on margin, leverage, short and do everything that's fun on the markets. Unfortunately the hedge fund plays around with your money, and charges exorbitant fees into the deal.....
betting, lottery, casinos, well at least you know what you are dealing with here, as no casino will promise you a return on your money. Here you can play, and enjoy it as well. But would you do this with your retirement nest egg?

None of the above systems work, all of them an safely be described as a loser’s game.
But Wall Street spends a lot of money not telling you these facts, as all the companies involved in that huge machinery depend on your ignorance.

Associated with the whole investment industry is the financial media.
The financial media loves new investment styles, hypes and the like, even more, it needs them, as you can't sell weekly copies of a magazine with a fat headline on the front page of every issue touting:
"Buy Index Funds, Cost Average And Then Forget Your Investments"
It gets kind of boring after the third week.

Never the less there might be a very valid reason to indulge in your desire to gamble, as index investing is everything but exciting. But if you do, put a very small percentage of your portfolio aside, and go ahead, buy that whispered tip of a hot stock your neighbor heard about...and when it's all gone, lick your wounds and forget about it.
Even better; go and play the lottery; there you know with almost 100% certainty that you are going to loose all the money invested. And you can play for a very modest CHF2.00.