I have been spending a good amount of time lately playing around with jQuery plugins. It can very useful to create a plugin, especially if you are going to be reusing the functionality in many different pages/sites. I have created a plugin called One Show Hide, which will hide html elements and add a show/hide link to toggle the visibility.
This plugin helps to solve the issue when you have a really long list, but only want to show the first 10-15 items, and hide the rest. And give the user the option to see the hidden items by clicking a link.
Its a very basic plugin, but can be quite useful and is very easy to implement.
jQuery has a huge plugin population and some can be quite advanced. This plugin is very simple, but it gets the job done. Please check it out, give it a try and let me know what you think!