Since a longer time I am working on a neural net library. The goal was to keep the library as simple as possible to allow the creation of many kinds of networks.
Furthermore I implemented nearly everything which is needed to export the net (which could be very assymetric) to matrices, which could be calculated by GPUs.
More project details could be found at: http://code.google.com/p/annetgpgpu/.
Now I am looking for ideally some co-interested people. The nearer goals for the future are: to add python bindings and implement a neocognitron with CUDA implementation.
Well I guess there are not many people interested in neural networks, but a nice side project could also be the implementation of something usable for stock market prognosis or something else.
If someone wants to contribute feel free to write me.