Does Craft have a server-side queuing system? I am wondering if Craft/Yii has some sort of built in queuing system for apps that need to do additional processing that could hang up the UI or make the user wait unnecessarily. I am looking for something similar to Laravel Queues. Does Craft have something similar built in? If not, I think queues would make a great addition to the API.

http://laravel.com/docs/queues
Not so much true queues, but Craft does have the (completely undocumented) concept of Tasks, which are meant to be used for potentially long running tasks that don't need to execute immediately.  Plugins can create and register tasks to run.

Here are some questions discussing them:

My tasks don&#39;t seem to be running as a background process

How to add a subTask to an already running Task?

Triggering the start of a task from a CRON job

You can view the TaskService in craft/app/services/TaskService.php and you can see examples of Craft's own tasks in craft/app/tasks.

Also worth noting that proper support for queues at the framework level looks like it's on the roadmap for Yii 2.1.