Altar of the Lunnotar: For this you will need several great prophets, a high productions city, possibly great engineers, plus good or neutral alignment.
When a great prophet is available, one option when in a friendly city is to build the first stage of the altar of the Lunnotar, which consumes the prophet as a religious shrine does. When another great prophet is available, if it is moved to the city with the first stage of the altar, and a certain technology is reached, the second stage can be built. This process continues through the different stages of the Altar, until the final stage. The final stage must be built, and possibly great engineers can speed its construction.
Tower of Mastery: This victory involves building four separate towers, each associated with, and requiring one of each type of mana, in the categories mentioned above. Once these four towers are built, the final "tower of mastery" becomes available, and once built, it wins the game.
To build the tower, you will somehow either have to get all 16 types of mana needed for the four individual towers, or get metamagic mana and enough mana nodes that you can cover all requirements for the towers. Using dispell magic, you can convert raw mana to a particular type, build the required tower, than convert the node back ot raw mana, get the next set of required mana, build the next tower, etc., until you have all the four sub towers necessary.
(It's a bit complex sounding if you're new, so hopefully the example will simplify things:
Say you are playing as the Amurites, who start with metamagic, fire, and body mana, and you are able to found, and get great shrines for, the Order and Council of Esus religions. Religious shrines, in addition to other effects, provide mana.
With these religions, and your palace, you now have metamagic, body, law, fire, and shadow magic, which provides 1 required mana in each category, meaning you only need 3 raw nodes to build all towers.
If you research, say, necromancy first, you can convert these mana nodes to entropy, death, and chaos, which with the shadow from Esus, allows you to build the tower of necromancy.
Once you get mages, you will be able ot give some of them dispell magic, which can convert the three nodes back to raw mana. You will than, if you've researched elementalism, be able to convert the nodes to water, earth, and air, and with the fire mana given automatically, you can build the tower of elementalism.
A similar process occurs with the divination and alteration towers. I don't remember exactly what the requirements are for these towers, as one of the mana types listed under "divination" above is actually required for the alteration tower, but the building process is generally similar.
Once these four towers are built, and the Strength of Will technology is researched, the final Tower of Mastery can be built, winning the game.)
I think that covers the unusual victories, as the other ones are in regular civ, but may have forgotten some.
