Rocky III is a neuronal modelling simulation environment I wrote. The zip-file includes executable, source, manual and example script file. The underlying equations are based on Wang (1999).

Networks of the simulated integrate-and-fire neurons can display interesting oscilatory behavior like this:

Each line depicts the time-course of the membrane potential of a neuron. The red bars indicate a spike. Neurons with a red label are part of an interconnected excitatory set. The blue labels indicate neurons in an inhibitory set excited by the excitarory set, and sending recurrent inhibition back to it.The region in yellow reflects external activation to the excitatory set, initiating the oscillation. The purple region indicates external inhibition, showing that the oscillation can resurrect even after the absence of spikes for much longer than a period of the oscillation. The behaviour results from slow excitatory membrane dynamics interacting with inhibitory feedback. Here is a PDF containing some possibly interesting pilot results I found using the program.