great looking calendar widget

Hi Can anyone recommend a great calendar widget either free or paid for. I’m looking for one that has similar functionality to the one found on this site https://www.hertfordtheatre.com/events/2013/03/13/

So when you click on a date – it brings up a nice customisable page with image.

It’s for an art gallery and I will only be showing it as a widget in the side bar.

Thanks in advance.