1. I have too many aunts/uncles/cousins but we have a long (30 year at least) tradition of doing a family gift exchange over the holidays. After one too many years of forgetting who I had or having my mom get asked by my aunt what my cousin should get me I build a website for my family that allows them to manage a gift list. Started as a super basic Django app and that was about 7 years ago and every year I add one or two features. Now it’s got all kinds things like notifications and will even help you track your incoming packages and know if they are gift wrapped or not.
Thing 2, was a wedding evite/website for My wedding. At the time I looked around and hated how impersonal all the evite options were, so I created a website with a cms that would give every user a customized, personalized experience. Invited to the rehearsal dinner? you see that dates and details. Are you one of my friends? You get the set of content with our inside jokes. It didn’t need any kind of login or passwords but provided everyone with a custom page. It also provided me with a full database to manage rsvp, song requests, track who gave us gifts (and what), etc. Yes my partner thought it was overkill (to answer that question) but it was super fun to build and ended up getting retooled for my sister in law’s wedding last year.