You're asking about the WEP key because you want Wi-Fi right? Well, the WEP isn't for the game, its for the Wi-Fi router in your house. It should be written on the bottom of it. Hope that's what you wanted!
A WEP key is usually a string of 10 hexadecimal characters. To find the WEP key on a computer, right-click your network and select Properties. On the Security tab, the WEP key can be found in the Network Security Key field.
No The WEP key is the key used to encrypt the wireless traffic, so people can't sniff the data and see what your doing. No WEP key, no connect to the network. No router password, and you can't log into the router to modify the WEP key.