Update: Due to an increasing number of english speaking visitors I have translated the main conclusion of this entry. Have a look at the comments.
Cpu Frequency Daemon is a very configurable program for throttling the cpu's frequency depending on "rules". A rule tests for battery state, cpu temperatur, active processes and so on.
For example, a rule which throttles your cpu when it's to hot might look like this:
If you're running a Drupal-based webpage which is completely restricted to authenticated users, Anonymous would get an "403 Access Denied" on every page he tries. But if you want your visitors to see a friendly login page (instead of just this error message and a small "login block") you might want to put the following code into your sites/default/setting.php: