Anyway to clear cache on Drupal 7 without any extra modules or even going to the performance page? I'm looking for a way to clear cache easily without installing any fancy modules or going to the performance page. Is there a URL I can just visit to clear the cache? Basically try to find the shortest and fastest way to clear cache without much effort.
drush cc all is the safest bet.

Visiting www.example.com/update.php will also clear the caches, but you need to be logged in.  Otherwise, this is a DOS vector.