Made a spreadsheet. Made a google form ("how has your day been?" + a text area) - they automatically add their fields to the spreadsheet. Wrote a short script that selects a random row at random, and emails it to me + a link to the form. Added a trigger that runs that script at 8pm-9pm daily. [if anyone wants the script, I'll post it - please improve it!]
Some flaws: 1. I couldn't work out how to automatically embed a form in the email directly, neither using their embed code (an <iframe>) - it works if they email it to you (which you need to trigger manually), but also gives a warning "you are leaving this page"; 2. also couldn't work out how to initialize the form with the random previous entry (a blog post said you could, but that was in 2008) nor 2. writing my own form (need an URL for the action: seems you need a form key, which you can't get, for security reasons(?))
Boy browser programming sure is frustrating: browser locked up twice had to set it all up again; 7 sec load time for pages; weird cursor movement for editing (and also not vim); along with the above limitation. Though it probably doesn't help that I don't know what I'm doing :-)