Tube Racer is a 3D game by Xerol which features a simple 3D line-segment ship and a very, very long (ex: infinite) tube which you fly through. It's single player, but with multiple play modes. The game configuration is excellent, and all play modes have different difficulty levels. The entire game is consistent with its feel. While playing the infinite mode, you may find yourself being asleep while at the same time, being completely awake. The graphical style of the game is very dreamy. Rather than wasting hours of your day awake taking a nap or browsing the internet endlessly, you may find yourself running your cursor over Tube Racer and playing it instead.
The game changes pace often. You'll go from riding in a wide tube, feeling relaxed and gazing easily at the graphics around you, to a narrow, extremely fast moving tube where the textures fly by at remarkable speeds. Even while you rush around with the keys, making sure you don't run into the tube's walls, you're relaxed and joyous at the sight and music around you. After making it through any one of these "phases", the music transitions perfectly, as do the textures used in the tube. Overall, it's a very relaxing, very worthwhile game to play, and I highly recommend it.