Fake, Hollywood-like hacking UIs
Arwes lets you create actual sci-fi like UIs for your apps, using React components. If what you want instead is just fun, fake UIs for pretending to do stuff (as they do with Hollywood films), GeenPrank’s Hacker Typer is awesome and fun. There’s also Hacker Typer, which is simpler and lets you put in whatever code you want it to type out. And Hollywood for local typing. Thanks to folks on Twitter for these links.
Notecalc is Soulver in your browser
I actually tend to use Calca more than Soulver, but the idea is the same: a notepad that lets you run calculations. It has a very different feel from a spreadsheet. Anyhow, you can use Notecalc right now in your browser, and I also heartily recommend Soulver and Calca.
Jupiter and Saturn
Spectacular photo of Jupiter and Saturn together, thanks to @JRehling, on their closest appearance in the sky in 800 years.