This is kind of oddware, in this modern day and age people joke about downloading more RAM, but back in the early Mac and PC days you could actually do just that.

Ram Doubler was a software suite that allowed Virtual Memory and Memory compression algorithms on Macintosh systems (and DOS/Win3x PC’s as well) essentially doubling the system’s available memory.  This was a very popular program, especially when you consider how much money RAM cost in those days, 1MB of ram could easily cost several hundreds of dollars.