We demonstrate, how to implement interactive applications with Reactive Programming (RP). Our RP framework REScala provides RP abstractions as an embedded domain-specific language in Scala. The demo begins with a simple animation to introduce Signals and Events, the fundamental RP abstractions. We incrementally evolve the animation into a Pong-style game, exploring increasingly advanced features of RP. We demonstrate, how RP enables declarative implementation of modular designs of interactive applications. We discuss additional benefits provided by these abstractions, such as strong consistency for concurrent applications provided by REScala. Finally, we showcase how REScala enables implementation of distributed RP applications, by extending the Pong-style game with local network multi-player.