Here is an idea I came across if you have a little one that likes to color. I'm always looking for ideas to keep my little ones happy while we are in a waiting room or an appointment/meeting where I need them to be happy and quiet while I talk and listen (doctor appointment, parent teacher conference, hair appointment, ...).
I have picked up little coloring books and blank notebooks to help keep my little ones busy. But a couple of weeks ago, while waiting at our pediatrician’s office, I saw a lady pull this out of her bag of goodies. There are four themes (these are the 3 my kids are most interested in right now but they also had Phineas and Pherb).
It's great because it includes a nice little coloring book, 4 crayons, and stickers all in a resealable bag for only $.97 at Walmart! It took me a while to find them but they were located in the checkout aisle.
My son loves the stickers but still needs a little monster truck or something to keep him happy. My daughter (who would color all day if she could) absolutely loves these! It's small enough to sit in her lap if there isn't a table and most of all it does not disrupt others! They have used them at doctors appointments and my daughter is excited to get another one today to use while it's my turn to get a haircut. These would also be great for airplane and car travel since they do not take up a lot of space and have the resealable bag to keep it all together!
Other ideas: I was once at a parent teacher conference where I saw parents of two little girls who brought a small tote full of coloring pages and markers to keep their little girls busy while they met with the teacher. I thought it was a great idea - but it could sometimes be a little bulky to carry around. I personally have tried game players (with headsets) that have worked well but depending on the age of your little one they may need help setting it up which takes time. When my kids were still really little I brought a portable DVD player with a movie they loved but didn't get to see other than at appointments. They were too small to use headphones so it was a little distracting but not as much as they would have been without it.