League of Legends: Dominion!

Dominion is a completely new game type and map based on controlling five fixed points. The map will be free and have an average game time of around 25~ minutes. Summoners will be able to try this new game hands on at both Gamescon and Pax Prime. I have edited in a lot of information from a handful of different sites, so have a look see around below.
Features of the new mode ( via  sk-gaming.com )

· Capture-and-hold gameplay: Summoners battle it out for control of five unique strategic targets, capturing points from the opposing team and defending them against enemy intrusion.

· An all-new map: The action in Dominion takes place in the Crystal Scar, a highly contested, war-torn mining village featuring stunning new art crafted specifically for the new map.

· Fast-paced action: Dominion is an accelerated version of classic League of Legends gameplay– matches last around 20 minutes, so gamers can enjoy a rapid-fire alternative to the more strategic, measured pace of Summoner’s Rift.

· Non-stop combat: From beginning to end, players will enjoy unrelenting skirmishes as they vie for control over the map– in Dominion, Summoners can expect an onslaught of one-on-one and small team fights.

· Down-to-the-wire victories: Matches of Dominion are competitive until the very end– late-game comebacks are possible and the outcome is always in question.

· Completely free: Like classic League of Legends, Dominion is completely free-to-play for new and veteran Summoners alike. Players will be able to use all their existing masteries, runes, champions and skins on Dominion.

Further reading : http://www.joystiq.com/2011/08/04/league-of-legends-dominion-preview/