JQuery Tutorials
Expandable Content Demo
This is great is you don’t have a lot of room, but want to make certain sections of your site expandable. Very smooth sliding effect. Sliding content from a partial height with jQuery
Horizontal / Side scrolling content Demo
Great for trendy sites. A more styled example seen at coda.
Custom Element Animation Demo
Allows you to preview custom transitions between different element classes. Definitely worth checking out.
Re-sizeableTextarea Demo
I can see a lot of good uses of this in interface designs.