You will need Mathematica's free CDF player installed as a plug-in for your browser in order to run these "computable documents".
Please note that the functionality seems a little limited. For example, the "Alt+Click" feature which allows one to add or remove centers interactively - while fine in the notebook versions of the two interpolation examples - does not seem to work in this CDF version.
A CDF that illustrates convergence of "flat" Gaussian interpolants to polynomial interpolants CDFs to accompany paper on positive definite kernels