Once in a while, I get to review a baby product that I wish existed when my kids were younger, and I'm thrilled to be able to give as a gift now. I was recently sent The Portable High Chair from ciao! baby. It's awesome. As a family, we enjoy camping and trips to relatives; we also would navigate church dinners and picnics, making do with laps and strollers. That worked, but it meant we were constantly cleaning strollers (and holding the food since there was no tray) or losing an arm while trying to keep our own food out of our daughters' reach.
This high chair is as easy to set up as a camping chair. It folds and unlocks in just a few seconds. Folded, it takes up only a few square inches, so it's easy for grandparents to tuck in a closet corner until it's needed, and easy to put in a trunk for travel. It's pretty easy to wipe down, and is designed to ensure that babies don't slip out. There's even a cup holder for sippy cups (although for young kids parents would have to help put it back in).
Other great options: drop holder to keep things on the tray, an accessory tray for holding small things and making it easier for them to stay on the food surface, a clip-on umbrella that works on just about anything, and diaper bags. If you're a sports fan, many college designs are available.
If you're a family that's on-the-go a lot, or a relative with occasional young visitors, this is a great option.