Nicely manicured fingernails don't fit into my lifestyle, but there's an entire subculture of nail art happening out there. Ten tiny canvasses, perfectly stamped, bejewelled and entered into competitions by nail artists all around the world.
Water marbled nails look like the easiest to accomplish at home with whatever Sally Hansen polish you have kicking around.
Inexpensive, fast and simple. You probably won't mind so much when the polish chips off the next day.
