Strange that your friends Poinsettia is still Pink after 1000 years, they dont even flower this time of the year.
They flower naturally in the Subtropics when the weather gets cold usually June here in Brisbane..
I would not worry about it yet, as those ones bought at Christmas would have to be forced in some way and are out of season

Hi REF what Misty said is true sadly, those types of Euphorbias only flower once a year usually in the cooler months.
The ones we see on the shelves in Aussie Christmas time have been forced to pretend they were in the northern hemisphere.
The flowers themselves are miniscule, the vibrant colouring is from the bracts which surround them (you've probably read all this already) and the bracts can maintain that colour for many months.
Some of the new hybrids are nice, multi-toned and supposedly "mini" but I still think some of the old-fashioned garden variety are the show-stoppers, especially if they've had a bit of care in keeping them from getting leggy, they do seem to hold colour for a long time.
Since they flower from the tips of existing - or new- growth, the idea is to try to stimulate more branches, by pruning and then by tip-pinching.
It's probably a little late in the season (and hot) to do any radical pruning now, but keep it in mind for next year and read up on prunings. But you could still do a little mild pruning of your plant to stimulate branching before autumn and look forward to a surround of colour in the cooler months.
As to your friend's plant, they are dead easy to propagate from cuttings, you might take some next visit (or beg some to send by post. Everyone beware handling as the white runny sap is quite toxic and esp harmful if you get it near your eyes. Also mucky to clean off and some folk get a rash just from handling it - best wear gloves.
Take some cuttings about 6 -8 inches long, whether with a growing tip or not doesn't really matter. You can wrap the cut end in a bit of moist paper towel if you are travelling with it or its being posted. Otherwise, the cut end does better if "hardened off" for a couple of days (like frangipanni and geraniums) to avoid fungus and damping off.
You can then proceed to strike cuttings and have a whole forest.

Thank you both for posting answers. To be clear, look I probably exaggerated a little about my friend's being in flower for 1000 years (specifically that it was in flower when I posted...I'm not sure it was, I just know that it had been in flower a few months prior and that it was a HUUUUGE old plant that seemed to have been living a very long time - so all I was reading on the net from USA websites (not ideal, but all I could find) was pointing to the idea that you need to do all these fancy moves if you ever want your green bracts to return to red/pink/whatever - lock it up in a cubpoard for 8 months in winter, don't even peak at it, it will only flower if kept pitch black, rah rah), it only lives a year really anyway... and none of that was making much sense given my friend's poinsettia! Okay, yes, I'll calm down, good call Mistymorn, and AlisonOz thanks for explaining that the one I purchased had been tricked into flowering out of season...it's aaaall starting to make so much more sense now. Great advice AlisonOz, I will indeed take heed and sort myself out a whole pink poinsettia forest... lovely! I'll report back when I've made some progress on pinking up my pinkee...

Just to follow up to say that those pink bracts did reappear - without any fancy manouvres being required from me. I guess I was just being overly concerned and ... dare i say it...impatient! So yes the pink bracts arrived without fuss when the autumn-winter seasons arrived, but I find they are gone already. I can't find much info on how long they're meant to last - I just assumed it'd be over the ENTIRE winter season. Perhaps not. Or perhaps my plant isnt well enough (it's hardly thriving) to have kept its bracts. I'll contact my friend with the 1000 year old pink poinsettia and ask if her bracts are still going strong, or if indeed the time has come for the plant to defoliate. I'm not sure why I'm sooo bad at 'poinsettia' but i really am. and i'm not sure why i can't find any info on growing it in subtropical Australia... (I thought there'd be heaps of info on the internet about doing so)

what size is your poinsettia? I'm about to prune back my tall (3+metre) poinsettias and wondered if you wanted any cuttings? I've got pink, red and pale yellow. I hate just throwing them out. I'm in Brisbane.

Thanks Annie - I"ve only just seen your post now (I tick the box to alert me to reply posts, but I guess it doesn't always do so?). Anyway, I guess your chuck-outs have long gone.

No problem, my poinsettia seems happier (but not at all thriving). It has for the longest time suffered from hooked leaves. I recently gave it a soil drench of trace elements and I think that has helped it more than anything I've done previously (lord knows how it survives my care!).

I googled at the time and thought perhaps hooked leaves were a calcium deficiency...never got to the bottom of that...

did you want some of my cuttings? I cut them back every year after they've finished flowering.