The Eurogamer Expo and gamesindustry.biz games fair has started selling tickets this week. You can buy a ticket for £5, which is donated to GamesAid, and gives you access to both events.
Games such as Fallout 3, Far Cry 2, LittleBigPlanet, Mirrors Edge, Motorstorm: Pacific Rift, Prince of Persia, Resistance 2, Tomb Raider: Underworld, Street Fighter IV and many more (with some still unannounced!) will all be playable.
The expo is part of the London Games Festival 2008 and will run from the 28th-29th October.