Chartle can deliver a wide range of charts which you can then embed in your website.
Here is an example of the type of chart that Hans Rosling has made famous in his analysis of UN data on his awesome gapminder web site. This simple data set looks at 4 sets of English and Maths scores over 4 years for 3students. The dynamic way the data points move make this type of visualisation quite useful.
I'm thinking of using this to do my annual analysis of achievement data for students over time - so hope that I can find an easy Excel import option. Looks to be a useful tool.