I was wondering about a date picker myself, but realized all I really needed was today’s date and a few previous days. For those like me, I thought I’d show what I did to get a drop-down with the current date and a few previous:
{{VALUE:{{DATE}},{{DATE±1}},{{DATE±2}},{{DATE±3}}}}
± instead of - is a subtlety that initially escaped me. Hope that helps someone out there!