I bought DH an advent calendar a couple of years ago which had a QR code behind every door that, when scanned, linked to a Christmas song. Yes, it was a little naff but it gave him a good laugh as I'm nuts about the festive season and he would listen to the tune on his way to the train each morning knowing I was having full on festive tunage whilst wfh 
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Unfortunately, I cannot remember the name of the company that I bought it from or find any emails relating to it. Does anyone know of any companies who make these calendars? Or something similar?