I also posted alternatives for the people on dial-up as the download is a bit large.
Savage 2
I recently discovered that the developers of Savage 2 have decided to release the game for free with an option to buy an upgraded account:
Savage 2: A Tortured Soul is totally free to play, but you have the option of creating a Prime account for just $9.99. There are multiple advantages to a Prime account, such as two additional inventory slots, unlimited play as Hellbourne units, access to player statistics both online and in-game, and the ability to download a replay of every Savage 2 match ever played! Spread the word, help the development community by supporting companies that want to make unique and innovative games.
From the Wikipedia Entry:
Players can choose between two factions: the Legion of Man or the Beast Horde. The initial launch of Savage 2 will feature the Conquer game type. This game is won by destroying the enemy's command center - which is either a stronghold or a lair. Each team elects one commander - which views the world top down - that should build defenses and upgrades to support his team. The other players of his team pick a class - which can be changed later - and scout for enemies and resources.
The only real resource is gold, which can be gathered from gold mines. These mines are vital for each team since they are the only way to build defenses and pay the upkeep.
Another task of the commander is to build garrisons or sub lairs, these serve as an additional spawn point - besides the command center. Good position and defence of these structures is essential: a well placed sneak garrison can give a team a huge advantage.
After the base is set up, the commander should give order to his team members and use a wide array of buffs and debuffs.
There will be a map editor available, which will allow for scripts and events and all sorts of things so players can create their own game types.
System Requirements
Minimum:
Supported OS: Microsoft Windows® 2000/XP/Vista
Processor: Intel Pentium® IV 2.2 GHz or higher processor
System Memory: 1 GB of RAM or above
Video Card: 128 MB DirectX 9.0-compliant video card
Sound Card: Windows-compatible sound card
DirectX Version: DirectX® version 9.0 or higher
Hard Disk: 2 GB available hard disk space
Guide:
http://www.savage2guide.com/index.php/Main_Page
Download (978 MB):
http://www.s2games.com/
---------------------------------------------------------------------
Savage: The battle for Newerth
Savage is the freeware previous game in the series. It has a similar style of gameplay to Savage 2. The download contains Savage and the community made Savage: Full Enhancement (SFE) modification that upgrades many features.
Download (153 MB):
http://www.newerth.com/?id=sfe
---------------------------------------------------------------------
Tremulous
Tremulous is a free, open source game that blends a team based FPS with elements of an RTS. Players can choose from 2 unique races, aliens and humans. Players on both teams are able to build working structures in-game like an RTS. These structures provide many functions, the most important being spawning. The designated builders must ensure there are spawn structures or other players will not be able to rejoin the game after death. Other structures provide automated base defense (to some degree), healing functions and much more...
Player advancement is different depending on which team you are on. As a human, players are rewarded with credits for each alien kill. These credits may be used to purchase new weapons and upgrades from the "Armoury". The alien team advances quite differently. Upon killing a human foe, the alien is able to evolve into a new class. The more kills gained the more powerful the classes available.
The overall objective behind Tremulous is to eliminate the opposing team. This is achieved by not only killing the opposing players but also removing their ability to respawn by destroying their spawn structures.
Download (96 MB):
http://tremulous.net/files/