One of my "must bring" items is the stall stopper - it's a great little invention to keep a restroom stall door closed if the latch is broken. It was very handy on our last trip to
Disneyland when one of the bathrooms had two stalls with broken latches and a line of people waiting - I was able to skip the line and use the stall stopper to secure the door, and got my then-3yr old DS on the toilet in time to prevent an accident.
It's great for also keeping the door securely closed if you have a small child who likes to fiddle with the latch while you're going to the bathroom. I use it for that more than I've needed it to fix a broken stall door, but I'm always thankful to have it when I do need it.
It's called a Stall Stopper