Here is a short history of programming languages complete with some illustrations and some background. It's fun, it's educational and it's free.
The history of programming languages is fascinating but it can be difficult to put it into any sort of order that makes sense easily. Now Rackspace has been kind enough to put together a graphic showing the languages along with some context. It has to be pointed out that there are some oddities and the selection of languages is fairly personal.
For most programmers computing really did all start with Fortran and Cobol, but the chart makes Basic look a little too close because while it might have been invented in 1964 but it really didn't catch on until the late 1970s. There were also important languages such as Lisp, Algol, Snobol in this period and far too many others to mention.
The final item Ruby on Rails is a complete red herring as it isn't even a language and its inclusion points out the missing languages - notably C#, Prolog, Visual Basic, Smalltalk and so on... feel free to add your own overlooked candidate for greatness..
Finally there is a chart showing how important the languages are now. It makes use of the TIOBE index which is based on the number of questions asked about a language. Clearly this measure has many flaws and you can make objections about the misplacement of your own favourite language but if you step back for a moment the chart sort of feels right to any practicing programmer. Notice that while Java may be the number one language, if you add C and C++ together they clearly become the number one mega language that overwhelms any possible opposition!
Click for bigger version (to close click the x)
Rackspace - full chart
History of Computer Languages - the classical decade, 1950s
Computer Languages by Committee - the 1960s
The rise of people power - Computer languages in the 70's
Towards objects and functions - 1980s