TiddlyWiki is a wiki packed into a single html file, written in javascript. This tool surprised me with its flexibility. The potential of this simple idea is extended by adding plugins, scripts, etc. To get started:  ◊  Introduction to TiddlyWiki  ◊  YouTube demonstration  ◊  Download TiddlyWiki To install plugins, TiddlyTools has a large selection of good, well maintained TiddlyWiki plugins, scripts, etc.:  ◊  TiddlyTools To add a LaTeX plugin for TiddlyWiki (My personal favourite), visit:  ◊  LaTeX TiddlyWiki For a good example of a TiddlyWiki used for scientific purposes, visit:  ◊  Deferential Geometry Enjoy! I certainly have.

"Trouble arises when either science or religion claims universal jurisdiction, when either religious dogma or scientific dogma claims to be infallible. Religious creationists and scientific materialists are equally dogmatic and insensitive. By their arrogance they bring both science and religion into disrepute." "Science and religion are two windows that people look through, trying to understand the big universe outside, trying to understand why we are here. The two windows give different views, but they look out at the same universe. Both views are one-sided, neither is complete. Both leave out essential features of the real world. And both are worthy of respect." Freeman Dyson "Religion is what keeps the poor from murdering the rich." Napoleon Bonaparte

Extracted from the official website: "Peoples Archive is dedicated to collecting for posterity the stories of the great thinkers, creators, and achievers of our time. The people whose stories you see on this site are leaders of their field, whose work has influenced and changed our world."  ◊  Peoples Archive

PlanetMath offers offline-browsable "snapshots" of the entire encyclopedia. The file size is around 100MB; so it can easily fit on a flash stick or whatever. The snapshots are updated daily with the latest version of the encyclopedia.  ◊  PlanetMath Snapshots

I have set up a forum dedicated to the discussion of the exercises in 'The Road to Reality'.  ◊  'The Road to Reality' Internet Forum