Under the proper conditions, surfactant molecules can self-assemble into wormlike micelles, resembling slender rods, can entangle and impart viscoelasticity to the fluid. The behavior of wormlike micelles solutions is similar to that of polymer solutions. The primary difference being that, unlike covalently bound polymers, micelles are continuously breaking and reforming under Brownian fluctuations and the imposed shear or extensional flow field. In this talk, we will discuss the behavior of a series of viscoelastic wormlike micelle solutions in extensional flows and describe several newly observed instabilities and flow phenomena unique to these fluids. In the first part of the talk, we will describe the behavior of these fluids in the homogeneous uniaxial extensional flow produced by a filament stretching rheometer. Like polymer solutions, wormlike micelle solutions demonstrate significant strain hardening and a failure of the stress-optical. At a critical stress, the wormlike micelle solutions filaments were found to fail through a dramatic rupture near the axial midplane. This filament failure likely stems from the local scission of individual wormlike micelle chains. We will discuss the effect that pre-conditioning can have on the response of these materials and demonstrate that the presence of branching in wormlike micelle solutions can significant reduce the strain hardening of the extensional viscosity. In the second part of the talk, we will describe how the extensional rheology of these wormlike micelle solutions can affect more complex flows by presenting a series of interesting new flow phenomena unique to wormlike micelle solutions. The experiments will include the observation of a new instability in the flow past a falling sphere, through a periodic array of cylinders and past a single cylinder. The flows are investigated through a variety of experimental techniques including the use of high speed imaging, particle image velocimetry and flow induced birefringence measurements.