I turned both of the portals into magnets that pull you in or push you out depending on the polarity of the portal.
This actually turned out to be a surprisingly fun challenge. There were a few tricky bits, but for the most part it opened up new and creative ways to solve the chambers.
To try out the magnetic portals yourself, first download this file.
Then, find the folder with the Portal 2 game files. You can do this by selecting Portal 2 in Steam, clicking on the settings icon, then Local Files and Browse.
Now put the file you just downloaded inside the portal2/scripts/vscripts folder. If there's already a file with the same name there, just delete it.
The next time you'll start Portal 2, your portals should be magnetic! When you're done playing, you can simply delete the file to return your game to normal.
Note: Starting from a save file won't work, you have to start a new game.