It was made with BGE and we created a fully functional stand alone executable for the conference. Here I present the .blend file, without the textures and sounds since they could not be re-distributed but you have the references in the .blend file if you want to re-create it like us or you can use your own textures and sounds.
You can tell in the .blend file the number of participants and they will be randomly drawn without repetition each time you click on the lever. In the same directory of the .blend file two .json files will be created, one with the list of the numbers still to be drawn and another for backup. You must delete these .json files each time you want to start a new raffle from scratch or if you change the number of participants, otherwise it will use the available list in those files. You can download it here to explore, change it or use it in every way you want, but please credit the authors.