For fans of the dated Orion and Orion like projects there is some hope though. :)
It is in the form of the Mini-Mag-Orion. It tries to address some issues with the old model and uses modern techniques for simulation as well.
The detailed report can be found as a pdf here (Andrews Space)
A quick summary of this paper:
It – if it becomes reality – can give us the entire solar system with travel times to Mars of a couple of months and to Jupiter in less than a year. In it you compress SMALL pieces of fissionable material (curium245 or uranium 235 or uranium233 or plutonium 239) with the aid of a pulsating super-strong electromagnetic field so that their small masses compressed into ultra-small volumes become supercritical and explode. They explode INSIDE a superconducting magnetic rocket nozzle. One explosion per second.