Electronic Games
There are many online games which can be bought for many different machines. PC's, Playstaion, Xbox and Wii are 4 machines which can play games online.
Some games for these machines are single player, which eseentially entails the game having a story which you play through. Depending on the size of the game, this could take 1 week to complete or months. Some of these games will then allow you to play the game again but on a harder level setting. This will make the game harder the second time you play it.
Many PC and console games now have online capabilities. These allow the gamer to play the game against other gamers from around the world. An example of this would be an army game, where gamers can go online and be part of a team who have to destroy the other team, or they can play on their own in a 'every man for himself' game mode. There are many variations of online play modes which allow every individual to play the mode that they prefer.
Most of these games will have some kind of ranking system so you can see how you fare against other gamers around the world. Some of these games then allow you extra 'perks' to help you become better at the game, but only when you complete certain problems online.
Online games invariably have the ability to create clans. These are basically a group of people or friends who enjoy gaming to play against each other online, or as a team together against another clan.