There are many situations while developing websites when you need to know how long a text string is: not how many characters it has but how long it is in pixels.
Regular Expressions (Regex) is a very powerful technology which allows you to process strings using patterns. It gives you the possibility of processing text in a relatively easy and manageable way. Depending on what you need to do, creating a single Regular Expression might save you some pretty complex programming.
Recently, there has been the Sample code acceptance checklist for IT organizations published at Microsoft TechNet. This checklist is meant to help IT organizations evaluate custom SharePoint solutions before they are deployed in the production environments.
Windows SharePoint Services v3 ships with a possibility to create RSS Feeds for every List. This feature is quite powerful as it allows you to create multiple RSS Feeds for one List based on Views. If you have worked with Lists at least a bit, you know that you can quite easily create a custom View using the standard SharePoint interface. Without any problems you will be able to define the filter and apply the sorting criteria.
Recently I've been working quite intensively with the SharePoint developer bookmarklets. SharePoint is really infamous of way too many clicks required to accomplish various things. Having shortcuts to the most commonly used functionality within one click saves really a lot of time.