A coder has created the classic strategy game Command & Conquer entirely in HTML5, running of Javascript. This means the game could be played in one of your browser tabs.
The developer has made a very impressive preview version allowing us to play the beginning of the campaign. The game starts with light tanks and a base unit which builds your base across the map in the locations you choose. You can build all the different buildings and troops to fight the enemy.
The game works best on Firefox or Chrome. If you’re curious, you can check out the source code too, here.