Sounds strange, I know. But I de-activated our custom plugin that actually controls how we login against our LDAP directory. So now I can't log back in to activate the plugin. :-(
So, I need to activate this plugin purely by accessing the file system or the database directly. I don't see in the wordpress tables where a list of activated tables is, and I don't see anything in the file system that indicates active v. deactivated plugins.
I've tried to parse through the plugins.php and the plugins API, but I can't tell what actually happens when a plugin is activated.