How to create random 2D data for testing classifier?

Hello

I would like to create random 2D data for playing around with classifiers. The result should be a (nx2) matrix where the rows are n data points and the columns are the features. There should be 2 or more classes and of course the data should be separable (to a certain amount).

How should this be done? Of course I could define the data points manually but this is somewhat cumbersome.