Leave Work Unassigned and See Who Steps Forward
Ugg.  I'm sorry about being negative but here are some protips:1. If a manager leaves work unassigned and you pick it up, prepare to have a LOT more work dumped on you in the future for no reward.2. If you pretend to be a manager with hopes of being made a manager, all that you will accomplish is you are going to end up doing your job AND your bosses job.  Your boss will look like a hero to his/her peers.  You'll kill yourself and won't be made a manager regardless.A better approach is to be smart about it.  Always negotiate the work and what you're going to get out of it ahead of time.  Maybe you just get some political capital, praise, or a positive review.  Don't just blindly do work you weren't asked to do thinking it will be rewarded.