My colleague Gunnar Schmidtmann has started his own blog, find it here. So far it is home to a bunch of interesting illusions (not tricks).
Also, it occurred to me that there was a sharp change in "level of required understanding" between my second and third posts. The second (Why do psychophysics?) was intended to be the start of a series of introductory-level explanations, which I do intend to continue sometime soon. However I'll also be wanting to post things at a higher level as well. For that reason I'm making use of the tagging system on here. The following posts in that series will all have the "introductory" tag (as the original now does).