Another Blender script - Mouse Scrub
Menu: Script Window->Misc->Mouse Scrub
Scrub through animation by moving the mouse (Hotkey E)
Useful for tablet users who cannot use alt+Mousewheel for scrubbing instead.
Usage:
Execute the scipt and enable the spacehandler (View->Space Handler Scripts). Now you can call the menu by pressing the E-key. Feel free to adjust this script to another hotkey if you like. You can now save your Blender-default settings (Ctrl+U) to make it persistent.