matt added a comment (well 3) to the Firefox Extensions I use (2007-08-09) post, asking for it since the page is down and googling didn't find anything, so here it is:
- In Firefox, goto Add-ons -> Mouse Gestures -> Options -> "Edit Gestures" button (at the bottom of the General tab, and click New.
- In the Gesture code textfield, enter: LR
- For Function Type, select: Custom
- In Gesture Name textfield, enter: Go to first page
Now, you only have to hold down the Right mouse key, and flick the mouse to the Left and then back to the Right!!