The official end of support for Drupal 6 has been announced, effective February 24th of 2016. This means that the official Drupal project will no longer continue to provide security and bug fixes for the platform.
If you continue to run a Drupal 6 website, this means that your software will no longer enjoy official security and bug patches directly from Drupal.org. However, security updates are still available from the Drupal 6 Long Term Support project, although that support will also expire at some point.
Move to another platform. Depending on the complexity of your website, the cost to upgrade to Drupal 8 can be in many instances comparable to the cost of starting again with a new website. Since Drupal 6 has been around for a while, these days it is possible to replicate much of the functionality of your Drupal 6 website on many popular platforms. The most similar and compatible platform to consider is Backdrop CMS, that originated as a fork of Drupal 7.
If you have any comments or questions contact us at reachout (-at-) drupalsix.org
If you still want to try Drupal 6, be advised that any code retrieved from the official Drupal website will have to be reviewed against D6 LTS security releases.
Official Drupal core 6.38, and modules & themes.
You can also download the latest patched versions from the D6 Long-Term Support project:
D6 LTS Drupal Core, and all D6 LTS projects.