@D-Rose: A good way to do some extra jump work during the week without devoting too much extra time / extra work-outs in is to do complexes with explosive lifts and sometimes even strength lifts, probably depending on the training phase. Lance had me doing it the last two weeks and I liked it a lot in complex with powercleans, jumpsnatches and half-squats. For example: 1 set of 3 reps in jumpsnatch, 1 minute rest, 3 vertical jumps, rest 5-10 minutes and do the next set of jumpsnatches etc. The jumping does not hurt the lifts at all, at most it limits the total volume of lifting slightly, but you go into the lifting set fully rested, so intensity can still be high.
For pure jumping / plyo sessions some form of structure can help as well. I used to just go and do a number of single jumps until a significant drop-off happened. An alternative I learned is doing a series with X jumps, with ~45 sec rest between reps, which is plenty. It primarily helps to stay focused, warmed-up and activated between attempts and gives the session a structure that I felt was lacking at least in my former sessions. You could also structure it in sets and reps, for example do a set of 3 with timed rests, regenerate, do the next set. Then move on to drops, bounds or other stuff. Keeping it nice and short probably helps a lot with fatigue management as well.
Just some ideas to try...
@Joel: Have you ever had substantial success with training with a weight-vest? I would imagine that for example a 5 lbs vest was just annoying and not really adding much resistance. Don't know, maybe I should try it.