Gambling is an activity that has existed since the beginning of time. In ancient Rome, for example, there were public games like the lottery and even a game of dice.  Many people enjoy playing online slots, because they are simple to understand. Each game has only a few rules and options, so they are easy to learn and play. Online slots are also playable at any time of the day, so they appeal to people who work at night, or others whose sleep schedule may be irregular.