HaH is a firefox extension that aims to make web surfing with a keyboard as usable as possible. Unfortunately HaH is no longer being maintained. LoL is a fork of Hah.
Version 1.5: I "added support" for firefox 4.0 by updating install.rdf. Everything seems to work.
Like HaH, LoL is released under the MPL version 1.1
The current development source is the git repository http://elder-gods.org/~larry/repos/lol
Questions, comments, suggestions? Email me.