Nanoshells, nanoeggs and nanocups. 

Nanoshells, consist of a spherical silica core coated with a thin gold shell and can be converted to nanoeggs by offsetting the core within the shell. When the offset of the core is greater than the thickness of the shell layer, the core pierces the shell, resulting in nanocups. Nanoeggs exhibit absorption and scattering spectra with multipolar peaks strongly red shifted relative to those of nanoshells and larger near-field enhancements. Researchers at the Hong Kong University of Science and Technology have developed a nanoegg with a hard cobalt shell surrounding a core of platinum and iron and found that it could safely deliver platinum, a known anticancer agent, to tumor cells. Nanoegg has been found to be seven times more toxic than the anticancer agent cisplatin to cancer cells. Synthesis of cobalt sulfide nanoparticles forms a hollow shell structure in the presence of nanoparticles made of iron and platinum and the resulting structures have a porous crystalline shell of cobalt sulfide surrounding nanocrystals of iron/platinum. The pores in the outer shell are large enough for water to access the interior of the nanoparticle. But hollow cobalt sulfide nanoparticles are not toxic to cultured human cancer cells.  
Nanocups 

Nanocups are very tiny, cup-shaped particles which can bend light. Researchers have found a way to make material incorporating nanocups that can bend light in a specific direction and no light bounces off the metamaterial back making the material invisible, Researchers have embedded nanocups which are the first true three-dimensional nano-antennas, and their light-bending properties are made possible by plasmons. 

Making nanocups 

To make light-bending material, polystyrene or latex colloidal particles are spread on a glass slide, layer of gold is evaporated at various angles on top of the particles, a layer of elastomer is deposited on top, cure and the slab is lifted from the substrate with the oriented nanocups embedded. 
Applications 

Nanocup metamaterial can transmit optical signals between computer chips; can be used to make enhanced spectroscopy and super lenses and to track the sun in a solar panel to focuses light into a beam that's always on target. 

Other shapes 

Ghim Wei Ho of the University of Cambridge Nanoscale Science Laboratory claims that we can grow nanowires, cones, rings, cups, flowers etc. Apart from their beauty as three-dimensional structures, detailed characterisation reveals a complex mixture of amorphous and crystalline material which not only determines the ultimate structure but also provides a unique material with potential applications for both electronic and photonic devices.