Bunny jumping is an unrealistic and very annoying movement in where the opponent hammers his space key, so he keeps repeatedly jumping.
In real life, you get very tired from doing such a thing, so I suggest that you make smaller and smaller hops unless you don't take breaks between jumps. I'm not gonna be able to do it myself, but it's certainly possible within the engine (Heat of Battle for CoD did it, and that's the Q3 engine).
Just a suggestion.