Map Link: Portal Feud
Gametype Link: None yet. I'll make some once I've playtested a bit more to find out what works best.

Welcome to Portal Feud. Two quantum scientists were working on a controversial portal transportation system between their labs. All was well until one of them let his dog pee on the other's lawn. To get him back, the second scientist slept with the first's wife. Things escalated until both decided to take a tropical vacation... not before hiring mercenaries to tear each other's labs apart, though. This is where you enter.

Try to get to your opponents' goal (flag, bomb plant point, et cetera... this map works with all gametypes) without getting killed. There are a number of ways into and out of each level of the base, some of which have to be unlocked. Good luck, soldier. The screenshots below should prep you for your mission.

Screenshots:

Map Overview
Here's the map from the top. What you have are two bases with 3 floors each, and a teleport system between the two. You're going to want to stay out of the middle as much as possible, since both teams have a turret to clear it out. Instead, it might be wiser to use the teleports. There's a grav lift that throws you into a portal that leads (randomly) to one of the two exit portals you see here. The one on the right will take you to the opposite roof (grab the sword on your way up). The one on the left will throw you directly into the second floor of your opponents' base (where the objective points usually are). However, there's a grav lift behind the second floor shield door which will throw you out until you destroy it. Shotguns and plasma grenades work well, but you only have a 45 second opportunity to get yourself or your teammates through. There's a brute shot behind that barrier on the ground level. Note the invisibility and the radar jammer (on the truck).
[img width=600]http://img149.imageshack.us/img149/4232/overviewnx9.jpg

Building Roof
Voila the roof: a good sniper's paradise... as long as the other team's sniper is gone, that is. Sniper Rifles spawn in the top left of thie screenshot, just up the stairs from floor two. There's also a needles and a bubble shield to help you cover your teammates in the field below. You can get here 3 ways. 1) the stairway from the middle floor. 2) the teleport jump from the opposite base. 3) the 'tubes' from the floor in the center of the arena. Always watch out for that invisible guy coming up the tubes.
[img width=600]http://img85.imageshack.us/img85/8374/roofrn5.jpg

Second Floor
Here's where the majority of player spawning happens: the second floor. This is the most defensible point on the map. Thus: objective points generally spawn here. Make sure to protect your grav lift here to keep those pesky attackers from getting to you immediately from their portal. You can get here though either stairway (roof or garage), or through the middle teleport jump. You can also make a hasty exit through the hole near the garage door (marked with a down arrow sign).
[img width=600]http://img85.imageshack.us/img85/642/middlenn7.jpg

1st to 2nd Floor Stariway
Here's the stairway between the second floor and the first. From left to right, a shotgun, regen, and shield drainer spawn in the boxes.
[img width=600]http://img292.imageshack.us/img292/8954/stairsen4.jpg

Garage
Here's the bottom floor of the buildings.This is not the way you want to enter if you can avoid it. Getting past the turret and up the staircase can be a difficult task. Unfortunately, a failed portal jump often leaves you with no option but to fight through the garage. The portal system's grav-lift-entrance can be seen in the back of this screenshot. How you enter determines how you'll come out. Your best bet is to jump just before you hit the lift. If you just want to jump to the middle of the map, you can jump and land downwards onto the lift and you won't have enough momentum to reach the roof or second floor entrance.
[img width=600]http://img292.imageshack.us/img292/7854/garagefw3.jpg

This is my favorite objective map so far (even better than Temple of Doom, I think, but it depends what you like), and it took me longer to get right than anything else I've made. Hope you guys have fun with it. And, as always, leave any comments or suggestions here. Feel free to bump the Bungie forums for me, there's no reason some screaming 12 year-old shouldn't enjoy this map, too, lol.