Just a little post today only to put under the light an initiative of the excellent dzone web site, ie Refcards.
Refcards are technical cheatsheets in PDF format on major developer topics. Up to now 13 Refcardz has been written and 8 other ones are planned til September.
Subjects are various like RSS/Atom, Glassfish, Rails, Silverlight, Spring, Depency injection and many others.
A simple means to understand quickly main aspects of many technics.