Disclaimer: HBO owns the rights to this concert, but they'd obviously allow you to record it from your TV onto a videotape, DVD, or onto your DVR. The method below should be comparable, but works entirely off the streaming Windows Media version on the HBO We Are One site. Don't go violating copyright law and redistributing this with 10 million of your closest friends on Limewire or whatever the kids are using today. But hey, if you already had a copy from some random peer-to-peer network, you wouldn't be reading this anyway, right?
Now that we have all that out of the way, here's a way you can save a copy of the concert for posterity, for later viewing on your portable media player, etc.
Minimum requirements: VideoLAN's VLC media player. Optional item: something to convert Windows Media files into some other format suitable for iPod, Phone, or whatever -- I used Format Factory, but there are several other options out there. And if you just want to watch it on your PC, you don't need any converters at all.
Procedure: head to the HBO We Are One site and start playing the streaming video of the concert. When it starts playing, it'll be in a popup window similar to the one below.
Once you've started it playing, right-click in the player window, and select Properties:
From the Properties dialog shown below, select the URL for the actual media file, and hit Ctrl-C to copy the address to the clipboard:
Now that you have the address to the Windows Media file HBO created, you can close the player window and start up VLC. In VLC, go to the File menu, and then to Open File...
Fill out the Open... dialog as shown below. Paste the Windows Media file address we previously got into the Open: text box, check the Stream/Save checkbox, and hit the Settings button beside it:
On the Stream output dialog, put checkmarks in Play locally and File. Click the Browse... button and pick a folder and file to save the concert in. You may just want to save it on your Desktop folder and save into a file named weareone.asf. Set Encapsulation Method to ASF.
Click the OK button to close the Stream output dialog. Click the OK button to close the Open... dialog. You should be back at the main VLC window now, where you can click the Play button. If all goes well, you'll see the video in VLC, and you'll see a weareone.asf created in your previously-selected folder.
Now you can watch the concert as it saves, or ignore it. Up to you. Regardless, in roughly 2 hours, you'll have a local copy of the show stored in the ASF file. Converting this with Format Factory or another tool will have to wait for another post. You may already know how to do this from other media conversions anyway.