How to quickly turn on/off active corners? Is there any way to turn on/off active corners?

I want to use it but someone is coming fix something and they are going to use my comp and they have big troubles with active corners (Windows users). 

I am on 10.6.2 and I do want to keep the settings so when they leave I can start using it right away.
I would suggest enabling Guest access or creating a new user account. If you create a new account, make sure it has non- administrator status! Do this by going to System Preferences -> Accounts, and clicking the + button at the bottom left corner. Alternatively, you can just have them log in as a Guest, which you enable from the same pane, and after which anything they've worked on will be deleted from your machine. In both cases, you don't have to mess with your account or any of its settings, and things are just as you left them once your friend is finished with whatever they need to use your machine for.