Market Hours web app
My most recent weekend project is called Market Hours, and is basically a real-time overview of opening/closing/lunch times for stock markets across the globe.
The app may be useful e.g. if you’re in Europe and you’re waiting for the NYSE or NASDAQ to open so that you can start trading.
It also gives you a pleasant countdown to opening bell (or to closing bell if the exchange is already open).
A simple color scheme is used; red if the market is closed, green if it’s open. Bank holidays, lunch hours (if applicable) and weekends are also supported.