Create a computational problem or borrow one from a simple programming competition from somewhere. Let people solve the problem using any way they want (language doesn't matter for instance).
Winner can be awarded to he (she?) who solves the problem; if that is not enough, then select the one who has the most efficient algorithm considering the language of choice. If the efficiency can't be measured or otherwise easily compared, a pure performance test will decide the ultimate winner, thus asm would a good choice for performance, but Basic can be much easier for designing a clever solution.
Example: Let a graph define directed paths from various cities (directional airlines for instance). The solver should be able to find the shortest route from any city to another, never going the wrong direction on a path. Two-way paths may exist by having two one-way paths.
The graph should be easily interchangeable so that the judges can use any input to test the solvers to prevent any hardcoding of specific data.
I would enter if I didn't know a good way of doing this in