Twenty years ago Arthur Ashkin, Steve Chu, and co-workers published the first paper using the single-beam optical gradient trap, now known as Optical Tweezers. Recently, in the near field, we have successfully demonstrated an approach that allows optical forces alone to assemble thousands of microparticles over macroscopic areas. Separately, the addition of simple holographic techniques has extended the basic capabilities of optical tweezing, making it a more viable tool for the assembly of micro-systems and the organization of specimens into user-defined structures. Our early efforts at filling a 3D lattice of optical traps led to an appreciation for the dynamics of injected microparticle streams, which yield a surprisingly successful method of sorting or re-routing within microfludic environments. Here, we present real-space studies of Brownian hard sphere transport though externally defined potential energy landscapes.