Plink! A multiplayer music experience by DinahMoe. Like ToneMatrix, but with friends (or complete Internet strangers!).
posted by spitefulcrow on Oct 9, 2011 - 16 comments

Super Mario Brothers X The greatest fan game tribute to Super Mario of all time! Gameplay video here. ^{hat tip to tigsource!}
posted by boo_radley on Jan 19, 2011 - 23 comments

Scrabb.ly: Massively multiplayer online Scrabble.
posted by sveskemus on Oct 15, 2010 - 37 comments

Oh woop de do it's Tetris on the internet. No seriously, Tetris Friends is awesome. [more inside]
posted by The Devil Tesla on Sep 8, 2009 - 48 comments

Friday Flash Fun: "'Make My Head Grow' is a two player battle game. Each player control a small angry guy trying to push the other guys box over the edge. As everyone knows smacking your head into the ground makes your head grow - maybe even enough to make your box move..." [more inside]
posted by Rinku on Feb 13, 2009 - 14 comments

Savage 2 is an innovative mix of first-person shooter, third-person action rpg, and real-time strategy. Teams consisting of 18 different classes, each with unique abilities, are divided in squads led by an officer, and under the direction of a single commander with a top down view of the action. Players must help their commander capture resources, advance their front line, and eventually destroy the enemy’s stronghold while accumulating experience and improving their abilities. Did I mention as of December 9th, it has become free to play? [more inside]
posted by paradoxflow on Jan 19, 2009 - 10 comments

Nano War: Infectious Flash Fun. Colonize blobs, send swarms, and win superior numbers. Free multi-player and level editor. Dangerously addictive. [more inside]
posted by The Whelk on Dec 5, 2008 - 24 comments

Shockwave Friday Fun - Tank Ball 2. (previously) [more inside]
posted by Samuel Farrow on Jun 19, 2008 - 16 comments

Paul and Dave, creators of the extremely popular Desktop Tower Defense flash game, have just opened up their new flash games site to the public! [more inside]
posted by flatluigi on Dec 6, 2007 - 18 comments

Multiplayer Jellybattle
posted by MetaMonkey on Aug 11, 2007 - 19 comments

Addictive game based in large part on discussion. Perfect for MeFi'ers in my book. There's trivia, there's politics, plenty of "strategery", and the heart of it is the message boards. Plus the added benefit of very few trolls, because to make it in this game, you need to be intelligent and literate. No wonder I'm addicted.
posted by Melinika on May 18, 2001 - 17 comments