KDice

It's a fun game I've been playing since yesterday.
Registration takes less than 2 minutes,
each round lasts around 5 minutes,
maximum of 7 players.

Link:
KDice

Taken from wiki:

KDice is a browser-based multiplayer strategy game based on Taro Ito's Dice Wars.^[1] KDice is programmed in Adobe Flash and AJAX by Ryan Dewsbury and was released in 2006. Gameplay in KDice is a simplified version of Risk with the primary goal of the game being to control every territory on the map.