Can't remember term

[rchandler]

I am having difficulty remembering the name for a grammatical term. I hope it is possible for someone here to help me.

In a sentence such as this - Rick, the guy writing this post, can't remember the name of something he should remember from school.

What is the name of term for the phrase between the commas? "the guy writing this post" For the life of me, I can't remember. Any help would be greatly appreciated.

[Mister Micawber]

.
an appositive
.

[rchandler]

Ah, that's it! Thank you very much. Coming up with that term has been driving me nuts.