I have a 950XL (love it) and was using a Microsoft Wireless Display Adapter (very cool) connected to some projection system that had a HDMI input and a USB socket, so you plug the Display Adapter into the HDMI input and the other end of the Display Adapter into the USB socket (to power the device), connect up and you are rocking. So I fire up Power Point (sorry Don Box) and run my slide deck.
Now it would be great to get the presenter mode on the phone so I could read my notes for each slide, but I don't and I don't think you can, or if you can, to be honest I'm not sure how you get it. To advance the slide, I just tap the screen on my phone, which works great, but you might want to be careful how you hold your phone as I accidental powered my phone down once in the middle of a presentation (bugger). The phone has a range of about 20 feet from the display adapter, which is ample as I tend to move around a bit when I speak.
This presentation was a little over 2 hours long and it maybe used like a 1/5 of my battery, I was quite shocked actually how little battery it ate.
What was really cool is I was able to demo one of the apps I'm writing on Continuum and then I switched Continuum's display settings to display the Phone's screen so I could demo the same app running on the phone, so if you are an app developer I would consider Continuum and the display adapter to be pretty much mandatory in your tool kit.
I really liked showing up without a laptop, just less stuff is always good. Toss in that a lot of hotels have big screen TV with HDMI/USB sockets, I can travel even lighter now, toss a fold-able Bluetooth keyboard and mouse in the suitcase and I'm good to go for keeping up on email and such while on the road.
In short like everything around the Windows Phone, Continuum is a shamefully well keep secret, but it does indicate that Microsoft has plans for the phone, so at least that makes me happy.