Capture the Flag (or CTF as it's known) is a gametype found in all Unreal Tournament games. The objective of each team is to capture the other team's flag and return it to one's own flag. A flag cannot be returned if one's own flag is stolen. If the flag carrier dies or translocates, the flag is dropped. Dropped flags can be picked up by the team of the opposite color, and they are reset if touched by the team of the same color as the flag or if left untouched for 15 seconds.
Variations include Vehicle Capture the Flag (vCTF) and Instagib Capture the Flag (iCTF). For a list of maps, see UT - Maps, UT2003 Maps, and UT2004 - Maps.
Layout and Item Placement
Capture the flag maps tend to be highly symmetrical. This is to achieve a perfect balance between both teams, because asymmetrical layouts often lend a certain bonus to one team or another. In addition, there are almost always multiple entrances to the flag area and they're often from different directions. CTF tends to have at least 2-4 lower routes between flags, 1-3 upper routes, a large central area with a valuable pickup, and enough room to maneuver easily around the flag. Most CTF maps are linear (so that the bases are laid out across from each other--the very best example is the (in)famous CTF-Face) and as a result the z-axis component and the degree to which paths overlap is extremely important. Both effect how easy it is for defenders to catch up to the flag carrier, as well as how easy it is for attackers to invade.
Capture the Flag maps range from the very rare 1v1 (CTF-1on1-Joust) all the way up to 32 players. The average is around 6-16 players. Depending on the size of the CTF map, there will often be at least two 50 armors and one 100 armor pickup, and finding a UDamage or a Big Keg-O'-Health is not uncommon. However, these items (except the 50 armors) are often difficult to reach or far out of the way to provide the necessary trade-off for reaching them.
Capture the Flag uses all standard "Deathmatch" weapons, and occasionally the grenade launcher or mine layer are thrown in there in custom maps. Players start with the shield gun, assault rifle, and translocator (unless disabled). In addition, all pickups are supported, including adrenaline. Often, the shock rifle, bio gun, or flak cannon is found close to each flag. The rocket launcher, if it exists in a CTF map at all, can be found pretty much anywhere, often opposite the flak cannon. The sniper, link gun, and minigun are usually found towards the center of the map, under the theory that they're more difficult to obtain there, which is justified because they're the more "hitscan" weapons and UT2004 is a hitscan-dominant game. Health vials and adrenaline are also prevalent, and health pickups can usually only be found near the flag (usually two of them) and sometimes, on larger maps, in the center.