Here's how to experiment.
First, download the php code for a simple data set generator.
Second, edit it to suit your data generation needs and upload it into ideone (remember, run it AFTER selecting php mode). Take care for large data sets, ideone will only output 1000 lines of output in its simplest operation mode.
Third, copy the output into a text file and save it (it's in ARFF format).
You are ready: go to the application, upload the ARFF file and start hiding!