What's a 20K game and what's SGL?
lol... sorry CQ
20K game: A 20K culture victory. You shoot for 20,000 culture in
one city, usually by spamming it with wonders and building only culture related buildings (temple, cathedral, library, university, etc). It is usually your capital (b/c the palace is good for some culture) or second city, since its nearly essential to start on building culture as early in the game as possible (a building's culture value doubles after 1000 years, and turns in the early game are worth more than turns later in the game, thus the culture builds on itself more. Make sense??)
This is opposed to a 100K culture victory, where the goal is to reach 100,000 cumulative culture within your empire. This is easiest done with a very large empire and lots of hurrying temples/libraries in as many cities as money/whipping will allow. Both 20K and 100K victories are grouped under "Culture Victory" (at least in vanilla).
SGL: Science Great Leader. If you are the first civ to discover a technology, there is a 3% chance (5% if scientific trait) of popping an SGL in your capital. He can be used to hurry an improvement, small wonder, or a great wonder. There is no SGL in vanilla/PTW.
This is as opposed to an MGL, or Military Great Leader, who has a chance at spawning when an elite unit is victorious in battle. In vanilla, this is the only type of great leader, and he can either for an army or hurry an improvement/great/small-wonder. In C3C an MGL can only form armies.
EDIT: Say, isn't there a thread around here that details a lot of civ acronyms and shorthand technobabble?