I'm making one too! I aim to make an interesting arena (Something Big's lacked. Pecon's is OK, but that's it), Interesting classes (Something Pecon's kinda lacks, i'm afriad) and have an overall fun experience. It's in super duper beta at the minute. All of the classes are inspired by other games, too!
What's doneAll current classes
What's not doneThe clock (Needs events)
The arena (25-40%)
Things that are brokThe control point (need to find the crap I need)
Balance?
Normals classesSharpshooter - Has a sniper rifle and a Scoped magnum - Stay at a long distance.
Pyro - Flaregun, flamethrower, Axe. You know what to do.
Medic - Oh come on you know what to do here.
Demolitons expert - Lay sticky bombs and launch grenades at the boss.
Assault - You have an LMG, a riot sheild and a knife if your sheild breaks. You also have a forgetton of health.
Ghost - You run fast, have a silenced SMG, a knife and a cloaking device. Must I explain?
Testing Robot - You have a portal gun. Some may think that this class is useless, but a clever player can do a lot of damage to 5/6 of the bosses. (tip:fall damage)
Pathfinder - You have jets, a small rocket launcher and a shotgun. Hit. And. Run.
Technician - Sentries. Clever placement is the key.
Brute - You kick ass at close range. Why? Two words: Auto. Shotgun.
Freeman - You're a bit fragile, but you have a lot of weapons - A crossbow, an SMG, a crowbar, a shotgun and a pistol. The equivalent of master cheif.
Boss classesAlduin - You're a forgetin' dragon!(Potential balance issue - uses the flying dragon, which has about 200 HP - May need to make myself a personal version of that datablock with less health)
Renderman - You're fast and pretty much invisible. Strike from the shadows. (Potential balance issue - May not have enough cloak energy)
Patriarch - A machine gun? Rockets? You're taking the piss. Invisibility too? oh great.
Master cheif - HE'S SO GENERIC! IT HURTS! The boss version of freeman.
Space marine - He's a loving brick. He's slow, but he's still a loving brick. And he has a bolter! Ammo is scarce, though.
Saxton Hale - Bash hippies' skulls in with a sledgehammer! (Notes: I need a "fist" weapon that does 200 damage, and his "BRAVE JUMP!")
Pictures?WIP screenshots ahoy!

-The lower half of the arena as of 7/1/12 - Behind-window area is subject to change

-The upper half of the arena as of 7/1/12
Is it up?Will be up at 3:00 GMT provided I don't have anything else that is more important.
What needs doing?-I need to get a way to make it so that choosing, say, Renderman, makes you look like him.
-I need you to play it!
CreditsMech Nexus A.K.A The first player to kill a Space Marine (Used Pathfinder - Direct hits help) - :DDD
Chrisbot6 - Events and a bunch of building
nadnafemaG - First person to die as a space marine (And some playtesting)
Everyone who played on the server