The first question on your mind is probably "what is a rogue-like?" Luckily it is an easy question to answer, it refers to any game created in the style of Rogue. What is Rogue? It is a game where you, the dungeon, monsters, items etc. are all represented by ASCII symbols. For instance, in most rogue-likes, an exclamation point ! stands for a potion. ? generally represents a scroll, $ represents money or treasure, etc. The dungeon is, for the most part, randomly generated (most games will have at least a few pre-defined areas). While they are low on graphics, they are high on content: not having to spend any real time on graphics means that all the programmer's (or programmers', as the case may be) time can be spend on more content.

The most popular rogue-like is undoubtedly NetHack. The newsgroup is extremely busy, and there are countless variants for the game. It's one of my favourites; I've even managed to ascend a few times. I have been playing this game for more consecutive years than any of the other games I have played. Your goal is to go into the dungeon, get the Amulet of Yendor from the Wizard of Yendor, and escape with it (this is also the goal of Hack (minus the Wizard), NetHack's predecessor) for your god. It is considerably more difficult than it sounds. Not only do you have to go down at least 50 levels into the dungeon, there are side-branches to complete including a mandatory quest. Then you have to go back up all those levels while enduring the attacks of the Wizard of Yendor. And then you have to get through the endgame. NetHack is the most complex and deep of any rogue-like; an item can have multiple uses (What can you do with a towel? you can wash your face and hands, you can wear it around your head to blind yourself, you can hit things with it, and maybe more.) and there aren't really clear-cut divisions between what is good and what is bad; even some of the worst things have good uses - that scroll of destroy armour can be used to make your armour more permanent, you can, perhaps, see things while blind that you can't normally see, even that nasty bit of tripe you found can help you make a new friend. NetHack has also spawned quite a few variants, since the code is freely available for all who want to look at it (be warned - I've heard it described as being held together with bits of string and a prayer), the most popular of which is Slash'em. Be warned again - while NetHack doesn't care if you win or lose, Slash'em wants you dead.

Another popular one is ADoM, which stands for Ancient Dungeons of Mystery. Considerably larger and longer than NetHack, your goal is to stop the incursion of Chaos into the world. You've traced the source to the Drakalor Chain, a small valley nestled in the mountains. ADoM features an overworld map, for travelling between towns, caves and dungeons. The problem is that you can't take your time - Chaos is always leaking out, and it corrupts things, including you. The farther you go into the main dungeon, and the more game time you take, the more Chaos energy your body absorbs, and eventually it will start to mutate - these are called corruptions. Some are handy to have; some make the game considerably more difficult for one reason or another. Items which can cure corruption are some of the most valuable and rare in the game. Once you succeed in your main quest (there are others which you can take), the incursion stops. You may then either leave the Chain altogether, or perhaps hang around for a little while longer and play some more. There are interesting artifacts to find, some fun (and sometimes absolutely maddening) quests to perform that aren't necessary but are very helpful, and of course you have to keep your god happy and stay alive (the two are definitely not mutually exclusive). ADoM's source code is not available to the general public to avoid having variants.

One I've just started playing is Angband, loosely based around the works of J.R.R. Tolkien. As you may guess from the name, the game takes place in Angband, which translates roughly to "Iron Hell". It is the stronghold of Morgoth. If you have read the Lord of the Rings trilogy, then you are familiar with Sauron, who is generally regarded as a force of pure malice who could bring complete ruin to the world. Well, Morgoth is Sauron's master. As you play, you'll encounter enemies native to Middle Earth, including orcs, hobbits, trolls, dragons and the Nazgul. You'll also find artifacts from Middle Earth, such as the Phial of Galadriel, the broken sword Narsil, and maybe, if you are lucky (or is it unlucky?), the One Ring. Even bigger than NetHack and ADoM, you have to go down 100 dungeon levels to acheive your goal; however, every time you enter a level, it is randomly generated, so once you've explored level 1 and returned to town to sell your findings, you'll have to explore it all over again once you go back into the dungeon. And the levels are considerably larger. As I understand it, Angband had few to no variants until the new programmer cleaned up the code, at which point there was a variant explosion. The most popular of these is Zangband.

More information on more rogue-likes can be found at The Roguelike Games Home Page.