By Subject
Natural Sciences
MedBioWorld
Biology-Online.org
Complete Works of Darwin Online
The Arts
Artlex (Art Dictionary)
Mathematics
Math.com
Algebra.com
Mathcasts
DimensionM
Business & Economics
BEOnline
Kapi Regnum is a browser based economy simulation set in the Middle Ages, which means it can be played on every computer with internet access. Downloads or plugins are not necessary. Registration is for free.
Literature
Bartleby.com
Gutenberg.com
Social Sciences
SocioSite
