Al Gore won't leave me alone. How do I unfriend him on Facebook?

Go back to Al Gore's shed and punch him. This will initiate a battle, after which he will stop spamming you.

Afterwards, he will still be your friend, even though the quest to remove him has completed.

When I went to his shed (u-store it - it's the first shed on the left when you get around to the back, facing Mackey's storage shed mmkay) it took me a couple of times to figure out how to actually beat him with his secret service agents.

The way I handled him was fight alongside Cartman. I was a warrior and would constantly do the attack to freeze him and then have Cartman do his fire tricks. When the secret service agents it's good to just take them out as you can and keep healing. I would bring Kyle in momentarily to get my shields and attacks up. I would also do the stomp trick as well to damage all of them....