The Captain’s Reception is not the same as the Gold/Platinum Reception that some previous posters seem to confuse it with.
The Captain’s Reception is usually on formal night before each dinner serving. They have free drinks in the atrium.
I did. two cruises this year: on the Dream (7-night cruise) it was put together with the shimmering seas reception. They had a little character show and blue drinks. On the Wonder, we had the normal Captain’s Reception on formal night and then a few days later the Shimmering Seas reception. That meant free drinks twice!! Also, the drinks on the Wonder were much better and more plentiful.