Here's a useful tip:
— mega so no fun (@marcowahlsoft) January 19, 2016
It's obvious, of course, but for me, at least, it's a subtly different way of thinking about it. Instead of the two step process of bringing up the Org calendar dialog and then choosing a date, you do it in a single operation: 【Ctrl+c .】
It's worth pointing out that the above operation inserts an active date. If you want an inactive date use 【Ctrl+c !】
fri 【Return】 instead.