Jim's guess is indeed great and fits perfectly, but is not actually it. Anyway... Grefter is close enough. It's Magic: The Gathering.
1. Many (most?) members of the DL have played this game. Very few members of the DL have played this game.
A bunch of DLers have played a game of Magic at some point, I'm sure. However the "video game" part was specifically referring to the original 1997 Microprose PC game also named Magic: The Gathering (
http://en.wikipedia.org/wiki/Magic:_The_Gathering_%28MicroProse%29 ). It's an interesting footnote perhaps best known as the last game at Microprose Sid Meier (of the Civilization series) worked on.
2. Travel the land. Meet new people and strange creatures. Beat them up. Take their money and their stuff. Get more powerful.
Build a deck, visit towns, travel beautiful Shandalar where centaurs and clerics and other dudes also are wandering around challenging you to duels. Win and take a random card from their deck (the anted card), lose and lose your ante. Bonuses and the like could increase your starting life total, you could buy better cards at town, etc.
3. Ante up, son. This duel is for keeps.
When Magic originally started Back In The Day (hence the grizzled prospecter "son"), you were supposed to play for ante. Few people actually did, though, and they sensibly removed this element from the game later. However, ante vs. the AI is just fine, where it allows your deck and collection to slowly get better by skill. You just get the excitement of hoping that your opponent antes the 1 Mox Ruby in their deck, followed by frantically trying to win the game, without the fear and despair on the other side (and the likely fistfight if you win).
Also Magic matches are called d-d-d-d-d-d-duels.
4. Lightning Bolt is pretty darn good.
Lightning Bolt was still insanely good when it was reprinted recently against the modern creature curve; it was even better against Pearled Unicorn level critters and the like of 1996. Plus to make the game go faster random crap on the world map has less life than the default 20, so you can just burn enemies out quickly. (Says a person who played maybe 30 minutes of campaign mode, but I know enough, so.)
Clue 5 would have varied based off how close people were. Probably would have mentioned something about "the 5 schools of magic" though.
