With the latest UNO Game by Mattel, you get 4 Blank Cards so you can assign your own rules. Why ruin the blank cards with one specified outcome when you can have many outcomes chosen out of random? This is a web application to randomize an outcome for your UNO blank cards. There are default outcomes pre-loaded with the app. You can add your own outcome too.
Link to the application – http://www.unorandomizer.com/
If you’re a developer and you’d like to contribute to this open-source project, hop in though https://github.com/thisarumahadurage/uno-randomizer.