We study the plasmon resonances of 10 - 100 (nm) two-dimensional metal particles with a non-regular shape. Movies illustrate the spectral response of such particles in the optical range. Contrary to particles with a simple shape (cylinder, ellipse) non-regular particles exhibit many distinct resonances ver a large spectral range. At resonance frequencies, extremely large enhancements of the electromagnetic fields occur near the surface of the particle, with amplitudes several hundredfold that of the incident field. Implications of these str ng and localized fields for nano-optics and surface enhanced Raman scattering (SERS) are also discussed. (C) 2000 Optical Society of America.