Urban Rivals is an online multi-player card game. Each card represents a character (some of which are based on real people or well-known fictional characters). Each character has specific Power and Damage values, and belongs to a clan. Some cards have abilities that are either triggered or countered by another card's ability.
Free registration gives a player 8 character cards; further cards can be purchased. 4 new characters, usually for 4 different clans, are added every two weeks. Sometimes 6 characters are added, usually for a new clan. Usually every 6 months a new clan will come out; the most recent is the Vortex clan.
The game uses affiliate marketing to encourage existing players to recruit or sponsor new players; such sponsors can offer bonuses for purchases of credits, describing them as cheat codes.
An associated comic book is published online every month, with 9 panels each on the Urban Rivals official website. Sometimes this comic gives out hints of a new character or clan.
Source: Wikipedia, Urban rivals , available under the CC-BY-SA License.