Glitches: Foundation - Outside:

Using the Warthog jump, as described above, you can reach Outside the map of Foundation and onto the walls surrounding it, or above the map, onto the purple roof. Both places, perfect for sniping.

To get Outside the map, and onto easily the best place for sniping on the map, because you can't fall off, and it is very hard to be shot from.

Get a Warthog in the map and the Lightning Sword, drive the Warthog into Room 1, by driving it up the Air powered elevators, if the Warthog gets stuck inbetween the wall and the Elevator, you'll have to blow it up and wait for the next one to come.

After driving the Warthog to Room 1 park it parallel to the Number 1 on the floor, with to wheels on the number and 2 off. Make the passenger seat facing the furthest away wall.

There are 2 fans on either side of the roof, do exactly as the Warthog jump tutorial says above, but get the 2nd player to run to Room 4. Aim up in between the first gap where the fan is.

Once the 2nd player has gotten to Room 4, get out of the Warthog and you should be thrown up through the gap near the fan and right up into the air, then you must try and land on solid ground and not fall back down again. If you do fall back down, keep trying until you stay up.

Once you're up there get the 2nd player to do the Rocket Lunge up to you, so that you can both be Outside.

If you are standing right above the fan, in an enclosed area, jump out of it and explore the map in detail, the only way to get back down is to go back down where the fan is.

Not a very economical or easy to pull off move in a serious battle, i wouldn't suggest it, but when trying to hide from enemies in a less serious match, this is a perfect idea.

You can also do the Warthog jump up to the purple concrete roof, try and conquer this, for a much more easily done routine and able to be pulled off in serious matches, but be careful.