Been sick all weekend so I stayed home and virtually did nothing but stay home and play Civ5. I managed to get a Turn 233 victory (1615 AD), but I reloaded a few times so I won't be submitting it as an entry (hey, it's a learning experience -- and I learned something each time -- like you don't want to attack a second city state because every city state increases hostility doubling the rate at which you lose influence, and the first city state I generally steal a worker from). Strategy is virtually the same as outlined by pagh80 above, and since he did such a detailed description, I'm only going to touch on a few things.
My opening took a slightly different variation, which is something I really like and might start trying even in normal games. Pottery->Calender->Writing->Mining->Masonry (hook up Marble) -> Animal Husbandry -> Trapping -> Philosophy -> (Great Library) Civil Service. (I do like the Theology idea too, getting to Renaissance ASAP is a good strategy).
Build Order -> Scout -> Worker -> Warrior -> Stonehenge -> (Purchase Library as soon as 420 gold is available) -> National College -> Great Library -> Oracle. May have been an extra Warrior in there, because I usually have 3.
By buying the Library and building the National College immediately after, it's a very strong boost to research. Scientists are now +4.5 beakers each, and because beakers don't overflow like in Civ4, I think micromanaging your scientists is really important. Also minimizing your turns wasted on filler techs is very important too. An example would be let's say you're generating 55-59 beakers a turn, and you have Archery (60 beakers), and Construction (110 beakers) available to research. I might have the wrong tech in mind, but bear with me. If you do Archery -> Construction, it'll take two turns each (and you'll lose the 55 beakers from Archery). However, if you do Construction -> Archery, during the 2 turns you get Construction, you might get a few population points, and push yourself to 60+ beakers per turn, and then you get Archery in one turn, saving you one turn.
In terms of research, everyone talks about beelining to the Cristo Redentor. However, for the purposes of getting the fastest Victory, Cristo Redentor will give you mostly happiness, and with mandate of Heaven, maybe about 25 culture per turn? I think the beeline should be for Radio, so you can purchase the Broadcast Tower for maximum culture output. Although someone mentioned above that you can deactivate a tree? I didn't know about that, and if that's true, maybe it's worth going to Rationalism for the 2 free techs, and then turning it off for Piety. This could be a very valid strategy if you have a coastal start and want to pop Globalization for the Sydney Opera House (and hopefully have an extra great Engineer on hand).
Purchasing vs. Building -- one thing to note is that the hammer -> gold ratio is much better the more hammers it cost. Monuments are 380gold for 60 hammers, (~6:1), where as Broadcast Towers and similar are ~1500 gold for 600 hammers (~2.5:1). Just something to keep in mind.
Lastly -- War, war, war. Unlike Civ4, there's NO penalty for going into war. Everyone likes using Horseman which is something I might change with my gameplay. I like getting Steel, and upgrading my 3 warriors into Longswordsman, but I can see the merits of using Horseman as they are much much faster -- and you can upgrade them to Camel Archers and Cavalry towards the end of the game. In fact, I sort of like staying in war unnecessarily long just to keep my guys getting XP. You also create more Great Generals. The first one I use for my wars, but everything else is Golden Ages.
I don't think I'll try this any more, but I'll definitely be back for the next HOF. There are some bugs that need to be addressed in a patch. One thing I found was, somehow I didn't have Aluminum in my borders, and I noticed that across the seas, Monaco had it, except it was being occupied by Siam. So I liberated them, and expected to get the Aluminum in return, since it was already mined, except when I liberated them, they gave me their luxuries, but not their Aluminum! So I had to Annex a city that had Aluminum nearby, buy the tiles, hook it up, buy my Hydro Plant, and then raze/sell the city. Ugh! I'm definitely hoping by the next time a HOF Cultural Victory is around, that we'll be several patches in.
My opening took a slightly different variation, which is something I really like and might start trying even in normal games. Pottery->Calender->Writing->Mining->Masonry (hook up Marble) -> Animal Husbandry -> Trapping -> Philosophy -> (Great Library) Civil Service. (I do like the Theology idea too, getting to Renaissance ASAP is a good strategy).
Build Order -> Scout -> Worker -> Warrior -> Stonehenge -> (Purchase Library as soon as 420 gold is available) -> National College -> Great Library -> Oracle. May have been an extra Warrior in there, because I usually have 3.
By buying the Library and building the National College immediately after, it's a very strong boost to research. Scientists are now +4.5 beakers each, and because beakers don't overflow like in Civ4, I think micromanaging your scientists is really important. Also minimizing your turns wasted on filler techs is very important too. An example would be let's say you're generating 55-59 beakers a turn, and you have Archery (60 beakers), and Construction (110 beakers) available to research. I might have the wrong tech in mind, but bear with me. If you do Archery -> Construction, it'll take two turns each (and you'll lose the 55 beakers from Archery). However, if you do Construction -> Archery, during the 2 turns you get Construction, you might get a few population points, and push yourself to 60+ beakers per turn, and then you get Archery in one turn, saving you one turn.
In terms of research, everyone talks about beelining to the Cristo Redentor. However, for the purposes of getting the fastest Victory, Cristo Redentor will give you mostly happiness, and with mandate of Heaven, maybe about 25 culture per turn? I think the beeline should be for Radio, so you can purchase the Broadcast Tower for maximum culture output. Although someone mentioned above that you can deactivate a tree? I didn't know about that, and if that's true, maybe it's worth going to Rationalism for the 2 free techs, and then turning it off for Piety. This could be a very valid strategy if you have a coastal start and want to pop Globalization for the Sydney Opera House (and hopefully have an extra great Engineer on hand).
Purchasing vs. Building -- one thing to note is that the hammer -> gold ratio is much better the more hammers it cost. Monuments are 380gold for 60 hammers, (~6:1), where as Broadcast Towers and similar are ~1500 gold for 600 hammers (~2.5:1). Just something to keep in mind.
Lastly -- War, war, war. Unlike Civ4, there's NO penalty for going into war. Everyone likes using Horseman which is something I might change with my gameplay. I like getting Steel, and upgrading my 3 warriors into Longswordsman, but I can see the merits of using Horseman as they are much much faster -- and you can upgrade them to Camel Archers and Cavalry towards the end of the game. In fact, I sort of like staying in war unnecessarily long just to keep my guys getting XP. You also create more Great Generals. The first one I use for my wars, but everything else is Golden Ages.
I don't think I'll try this any more, but I'll definitely be back for the next HOF. There are some bugs that need to be addressed in a patch. One thing I found was, somehow I didn't have Aluminum in my borders, and I noticed that across the seas, Monaco had it, except it was being occupied by Siam. So I liberated them, and expected to get the Aluminum in return, since it was already mined, except when I liberated them, they gave me their luxuries, but not their Aluminum! So I had to Annex a city that had Aluminum nearby, buy the tiles, hook it up, buy my Hydro Plant, and then raze/sell the city. Ugh! I'm definitely hoping by the next time a HOF Cultural Victory is around, that we'll be several patches in.