I'm sure we all have them, especially those of us who have worked in LTC. Here are some of mine:
climbing into other residents' beds and taking a nap...one time we found the resident sleeping in a bed that was already occupied by the resident it belonged to--they were both sleeping in there!!
putting pajamas in the toilet, then having an extra-large BM right on top of them
taking a cup that had some medication mixed in juice, then turning to the person sitting next to her and saying "here, you can have this"--fortunately I was able to take it back before the other resident could get a hold of it
wandering around in the hall and grabbing people's butts
blowing nose into a tissue, then using same tissue to "clean" nurse's station counter
What other funny/crazy things have you guys seen dementia patients do?