jquip : Smaller, Lighter, Faster, more modular jQuery - include only the parts you want! Don't use it, Don't include it.
Rickshaw : Rickshaw is a JavaScript toolkit for creating interactive time series graphs.
RAWGraphs : RAW is an open web tool to create custom vector-based visualizations on top of the amazing d3.js library.
Primarily conceived as a tool for designers ...
Handsontable : Handsontable is a minimalistic approach to Excel-like table editor in HTML & jQuery. Now with column and row headers!
Sammy.js : Sammy is a tiny javascript framework built on top of jQuery, It's RESTful Evented Javascript.
Morris.js is a lightweight library that uses jQuery and Raphaël to make drawing time-series graphs easy.