When I start a new class, I take pictures of my students with nametags made from notecards to help me in learning names. I got serious about this when I started teaching large sections, since there's really no hope for learning so many names without some kind of a system. (Unfortunately, it doesn't help that much in large sections; I still can't learn all the names by the end of the semester.)
I usually ask students to include their full name on the back of their card, together with one interesting fact about them. (I'm hoping to find something to associate with the student.) I leave it pretty open; the students can respond with anything they want.
Now the definition of interesting is pretty open to interpretation too. A favorite response in a sophomore level class is "I am a sophomore." If the class is intended for major X, then I get a number of students who answer "I am an X major." And for some reason, I used to get "I like horses" from about twenty women each semester in one large section I used to teach. (I don't know why that response was so popular.)
Recently I've been processing my note cards for this semester. It's a long process of cropping pictures and copying the tidbits students share into an Excel spreadsheet where I keep their grades and other information. I noticed recently that someone else I read has been writing about the asking the same question. (Interestingly, it's another math teacher at another school. Go figure.) She has apparently been getting somewhat better answers than "I am a sophomore X major."
But I have gotten interesting answers. I usually find out that I have students playing in a variety of varsity and club sports at the university, or who are in the marching band or another musical group. I frequently have some student who is widely traveled: "I've been to 5 continents", or "I've lived in 13 countries, and underground for 3 days." I usually have a polyglot or two: "I speak 8 different languages." (These students are generally not from the US.)
I also find out that some students want to be orthodontists or vets, love animals, can't swim, hold a swimming record at their high school, hate math, love Jesus, that some are an only child and that some have a twin. (I often have more than one twin, although usually not as a set.)
I find out some of my students are making long trips to come to school. I get students who are from India, Pakistan, Korea, Guatemala, Peru, Turkey, Singapore, and a host of other countries. Some also tell me they grew up less than 30 miles from this school.
Some cards are blank. Years ago I had a student with blue hair and a nose ring write "There is nothing interesting about me."
I usually have some students who I think should be very tired by now: "I have been singing for nine years." "I have been playing soccer for 12 years now." "I have been playing piano for 11 years."
But my most interesting response came a few years back. It just said "I pee in the bed." I'm not sure what that was supposed to mean, but I got nervous if the student looked like they were about to fall asleep during class.