Batch and Queue API are two similar APIs to process heavy operations without the risk to run into processing timeouts. Here is an overview about the general concepts.
You want certain content-types to no show up in Drupal search results? Here is a hook implementation to do so when using Drupal core search module.
There are some possibilities to change the structure of a drupal form. They are trigged at different times in the form building process, and therefor different things can be accomplished with those techniques.
Drupal media module fetches thumbnails for videos and stores them locally. Here is a snippet how you can access the thumbnail and render it using an image style.
Using the Webform module you can specify some description text for each form-item. Through trial and error I found out, that some HTML is allowed. However I took some time to find out how I can add HTML tags to this set of allowed tags.
Today I ran into an issue where a form was not submitted correctly. The form was on each row of a views page, and the view was cached using cache_actions module (which provides a cache which can only be cleared via a custom rule [from the rules module]).
Both modules, entity and field_collection, are programmed by the same guy. As one would expect, they work together very well.
Here is a snippet to redirect a user after a node save
Fago did a presentation about how to implement your own entity. Basically you would like to create your own entity when you need objects that have a different behavior to the existing entities like nodes, user or vocabularies.