Entanglement is a very relaxing game I discovered completely by accident. It's relaxing yet makes you think and has an easy to learn interface. It's perfect for when you're bored but don't feel like lulz, flamewars, or porn. And unlike a lot of other games, it actually looks artistic. The screen and music have sort of a Japanese feel to them. I'm growing somewhat addicted to it after only about 15 minutes of play. It's also free and no downloads required. One of the best time-wasters I've come across in months.