Elevator lines at conventions
1) Empty the elevators at the top and bottom floors. No going up to go down or vice versa. The process of emptying them won't directly speed things up, but as people figure out what's going on and stop misbehaving then the decrease in elevator misappropriation will improve efficiency. This idea requires 2 staff per bank of elevators.
1a) Put an attendant in each elevator to stop people from riding the wrong direction in the first place. This requires one staff per elevator.
2) Sort the waiting line/crowd by destination floor. You can't control which floors an elevator gets called to from outside, but if you only put even numbered floor people on elevator A and odd numbered floor people on elevator B then you will decrease the number of stops of each elevator by about 25%. This idea requires 1 staff per primary elevator boarding floor (such as the three bottom floors in the Dragon*Con Hyatt).
3) Designate one elevator for special circumstances. Wheelchairs, large carts, etc. Put an attendant in that elevator, and give them a fire key. This way they can decide exactly which floors to stop at, without the elevator stopping for calls along the way.
4) Ask the hotel to disable elevator calls and destinations for floors that are served by escalators. Put an attendant on those floors with a radio, so that the special circumstances elevator can come down to pick up people with carts or wheelchairs on those floors. This will reduce the number of stops of each elevator by 5-10%, weighted towards "sorry, elevator is full" sorts of stops. This idea requires 1 staff per disabled floor, and either an implementation of idea #3 or some other override.
5) Incentivize use of the stairs where possible. Something as simple as a raffle ticket for each walk up the stairs, even with an expected value of a few cents per ticket (that is, $100 worth of prizes after giving out 2000+ tickets), would have a significant impact. This requires 1 staff per stairwell.
I'll edit this post as people make further suggestions, and hope to send it to various convention staff members when it is "finished".