Jamescryer.github.com/grumble.js/ Originally written for Huddle.com, grumble.js provides special tooltips without the usual limitations of north/east/south/west positioning.
A grumble can be rotated around a given element at any angle, all 360 degrees. Any distance can be specified. Any CSS style can be applied. There's auto-magic size adjustment for use with localised text. Tooltipsy - jQuery tooltip plugin for control-obsessed designers.