Ok, I got cast in a play, and (I'm not complaining I swear) all my character does is recreate what happened the day before, and after that has two one liners that include a joke, and then reaffirming how cold it still is. Now I know I need to really delve into the details of what my character is describing, but still stay conscious of what is going on in the room.

Is there anything else I should concern myself with my character, who only tells a story when he's onstage, in a nutshell?

P.S.- I know I'm being vague on the details, but that's because I'm just looking for technique, not your own interpretation. Thanks!

Every single thing you refer to in the text must be created by your imagination with exhaustive specificity or it will be indicated, not truly experienced. But without more details, thats the only advice I can give. I'm very cautious about advice on these things, because that's the responsible position to take on a message board. - Jason

As nobody of us knows what play it is, here are some ideas. (there is no nutshell solution to this)

Where is that place? What year, what time of day? What's the season? What kind of building is he in?

What is going on outside or inside? (noises, movements by animals...)

Who is the character? Why is he here? Where does he want to go, need to go?

Is there really nothing that character has to do? Just sit? Or is he behind a counter, like a security officer? He could solve a crossword, then doodle with the pen when he is recalling the day before, he could try to make a heater work, warm himself up by getting up, moving around, maybe he has a cold? Does he have something to blow his nose? etc...

There are no limits, and you just take these examples as examples and make up your own thing.