"My ring just rolled under that large cabinet"
"This label fell off the wall"
"There's a display stand which keeps falling over"
"My walkie talkie knob won't stay on one frequency"
"Can you pop these posters up?"
"People keep looking through the keyhole to the new art gallery we're setting up."
Handy Gallery Attendant Tip #31
Always have a lump of Blu Tack (or whatever brand of sticky, tacky putty you prefer or your budget allows) handy about your person.
Also useful for shaping small comedy animals and leaving them for co-workers to find and then sculpt into new shapes.