Triple Triad from FF8

What was cool about Chocobo Racing was that it was absolutely pervasive throughout the game. It wasn't just something you did on the side; breeding more of the wee buggers let you experiment with more advanced breeds, until you got the ultimate Chocobo (I think it was gold) that you could use as a mount for travelling anywhere on the world map, thereby unlocking extra areas and getting extra powerups (including, and memory is really getting hazy now, the rather fine "Knights of the Round" summon). But yet it was also optional, you could run through the game without it and your enjoyment wouldn't really be diminished, so if the idea didn't really appeal it was something you could quite happily ignore. Just a perfect case of synergy between main game and mini-game.

I hope this counts as a minigame there are a few versions out there but the best online version in my opinion is littlealchemy.com, you essentially start out with the 4 basic elements and combine them until you have created in excess of 200 elements. An example would be combining fire and air to make steam, which in turn can be combined with something else to create energy. The game is highly highly addictive. It has a balance of humor ( you can create master yoda from starwars or super mario) as well as involving a lot of thinking (although there are ways to cheat)! other reasons why it is great is because there is no story line you can jump in as many times as you want, it costs nothing and it is very easy to get going.

Give it a go!!!!

PS I think it wouldn't be incredibly difficult to develop it yourself - maybe a weekend project if you fancy it ;)

Pazaak was a great card game from the Star Wars: Knights of the Old Republic video game series.

Inline with alchemy-like stuff, the Paper Mario rpg games let you mix different items to cook a new meal. There were probably 200 or so different results (with each recipe being automatically recorded in your cookbook when discovered), and the items were really great too. Have a Super Shroom that heals 10 health, and some Maple Syrup that heals 10 flower points (mana)? Mix them to make a Maple Super that heals 10 of each. Or, go get some Melons from Yoshi's island, and some Cake Mix from the Shy Guy's Toybox area, and you can make Yoshi Cookies that are fairly decent (15hp, 5fp I think), and additionally are used in a sidequest.

There are a couple sidequests that require cooking, but even aside from the sidequests, I found it a excellent way to make your items more useful and powerful, and so would frequently use that even without the sidequests.

On the flip side, Paper Mario also had a Oink Oink farm (brightly colored pigs). You can buy an Oink Oink egg, and it'll hatch a second later, and if it was good, you'd get a good item. You're trying to get the golden colored one, but there are a few others that I guess give decent items. I disliked it very much because it's completely random. "Insert money -> Sorry, you got junk -> Insert money -> Sorry, you got junk -> Repeat until you are out of money or got something good."

I like my mini-games to actually be interactive games, or else have predictable results like the cooking example. Interaction with randomization is fine, non-interaction with no randomization is fine, but no interaction and randomization is not fine.

Slot machines? Boring. It's gambling without interaction, and the odds are always against you, so long-haul you always lose and there's nothing you can do about it. Even when the odds are in your favor, it's still boring, as you just get more and more money until it becomes pointless.

Poker, Blackjack, or Pazaak? Fun. Random with interaction. The fun comes from the delight of getting a good hand to pulverize your opponents, or from the challenge of being dealt a poor hand and through skill coming out on top (or at least not coming out on the bottom), and being rewarded with more money.

Alchemy? Fun. No randomization, no interaction, but predictable. The fun comes from discovering and exploring the ingredients (or finding secret recipes from NPCs) and being rewarded with items. You never get too much items, because you still have to hunt down the ingredients, and the work to get the ingredients should be almost as much work as the quality of the item produced.

(Just realized that with Poker you risk money to gain money, and with Alchemy you risk items to get items)

This isn't really a mini-game per-se, but the GW2 jumping puzzles and vistas (which are generally mini-jumping puzzles) are pretty awesome. Pretty much since Asheron's call I've spent a lot of time jumping around, and it's great that somebody finally made some sort of reward for what I'd probably end up doing anyway.

It also was a great excuse to show people some of the great environments that are easy to overlook.

edit: example of jumping puzzle

the card game in Might and Magic 7. Someone made an offline version of it, I think. But the AI for the offline, IMHO, bad. Or maybe uses different calculation for random and luck or something, it just not as fun as the ingame version.

One of my favorite minigames of all time was in Spiderman: The Movie (the game) for PS2: Spiderman bowling. You swing from the ceiling of the bowling alley, and hurl yourself into the pins/random baddies to knock them over. It made the whole game worth owning; I don't think I ever even went back to story mode after unlocking it. Wonder if I still have it somewhere...