Since it is the 35th anniversary of the 4004 microprocessor, Intel has released the schematics of that chip, as well as a simulator written in Java. Details are available at the unofficial 4004 web site: http://www.4004.com/.
Apparently the Intel Museum [http://www.intel.com/museum/] is also going to feature a giant reproduction of the Busicom 141-PF calculator, which was the product the chip was designed for.
Really fascinating stuff. . .