Things I occassionally stumble upon: xv, the X11 image viewer, was one of the first pieces of Unix software I had to deal with, back then in the CS computer pool of my university, running CDE desktop on Sun Solaris workstations. This has remained a memory for two reasons: At first there was that image browser dubbed "Visual Schnauzer" (
http://mm.iit.uni-miskolc.hu/Data/texts/Manuals/XV/visual-schnauzer.html) as one of the first-ever thumbnail-based folder browsers I can remember. And then, there was that weird behaviour of the system caused by back-then a limited amount of colours that could be displayed and some visual applications utilizing color schemes of their own, so whenever you had an image opened in xv and would switch over to, say, Netscape Communicator for doing some browsing, the color palette of the desktop would change and, in a weird way, distort the color of the image displayed in the viewer - and vice versa.
Looking back, it all feels pretty archaic. Ages ago. And it's amazing to see the xv web page still around, and still sticking to its "old" visual style one got used to, back then...:
http://www.trilon.com/xv/ - not sure if the software still works, at least seeing the page last updated in 2009 makes continuos maintenance less likely.