I went back to college when I was 25 after the Army and had to get a place off campus. The place wouldn't let me rent without a guarantor, and my wife (of almost 5 years at the time) wasn't sufficient.
So I had to call my mom and ask her if she'd sign off on it, despite me having been living on my own for 7 years at that point.
It's one of those moments that still pisses me off well over a decade later, just like when we closed on our first house but they fucked up and didn't get the paperwork to the county courthouse in time, so we had to rent our own house for the weekend.
Edit: And actually, seeing the post above, my wife and her brother both got $40k from their parents a few years ago when we both happened to be buying a new house at the same time. Although a lot of that had to do with their dad having had leukemia for a couple years already and knew he was inevitably going to die, and wanting to give us an early "inheritance."