Distributed manufacturing service Ponoko has released a new material available for their 3D printers, with the self-describing name of "Durable Fine Plastic". We think this is a pretty cool material, because it's actually TWO materials in one!
The objects themselves are printed in a rather nice ABS-like plastic that has both "durable" (strong like ABS) and "fine" (smooth finish) characteristics.
The other material involved is a gelatin-like substance that's used for support. This gelatin may be swiftly removed by washing it off after the print completes.
Support capability is really important, as it permits all kinds of new object geometries to be printed. However, using this material requires a bit of design work: even though it easily washes off, you must ensure your objects have a hole through which it can be washed out. Otherwise you'll be carrying a lump of gelatin around forever.
Via Ponoko (Hat tip to Kristen)