I'm sure this has been asked but is there a place or service to store the games/items you've bought until you're ready to leave for the night? 

No, there is not.

Unfortunately one of the primary reasons downtown and connected hotels are in such high demand is because of easy access to the room for game storage.

A person could make a killing with a locker truck, charge by the hour, with limited size of storage.  :) 

Hey, Gen Con staff...there is an idea!  A room, storage boxes, numbered and either charge a flat fee.   

Yes, a package check room has come up many times.  Aside from any liability issues, and staffing needs, to have any meaningful impact, that is, to be able to serve even a small percentage of attendees, this would take away significant space from gaming, which is really not something I think any of us want.

Marian McBrine
Event Coordinator
Gen Con LLC

You have two options really.
Take it back to the hotel or take it back to your car.

Or Carry a large backpack

I try to spread out how I purchase things so that I don't have to carry too much with me at any time. Though if you park in a parking ramp or something similar, it should be fine to store in there for the day. Ive done it with no problems.

Or bring one of those huge rolling suitcases and drag it around behind you, with no regard for other people.  If you do this, be sure to leave it out in the middle of the path behind you as you randomly stop to look at something in the dealer hall, or to check your texts.
<Sarcasm Off>
:)

thank you all for this info.

We totally agree with you.  I can forgive the 'stink' and crowded halls, but seriously, if you are towing a wagon or suitcase you have now doubled your area of effect.  Not cool.