Calendar on right of screen – I want one back!!

I cannot for the life of me remember which version of WordPress it was.
However when I first started using it (even before it was called WordPress) by default there was the little “Calendar” on the right of the screen.
A day with a post was in bold and a day without a post remained in normal.

Since the 2.x series that doesn’t seem to exist any more.
I’ve looked through numerous plug-in’s etc for WordPress but just cannot find a way of brining one back (I totally reply on plug-in’s and cut & paste jobs because I really don’t know what I’m doing. I can upgrade my Blog software but that is about it).

Can anyone point me in the direction of something similar – a calendar module for the right-hand side of the blog.
I want one in addition to everything else that is there by default if at all possible.

Ta