Whenever I apply somebody else's big patch to review it, I obviously go ahead and revert the changes to my local Subversion working copy afterwards. Here's the line I use to do it, maybe somebody will find it useful (though I mainly blog it not to forget it myself):
svn st -q | awk '{print $2;}' | xargs svn revert(To be honest, I also expect about 17 comments now that tell me how I can do this more efficiently, or what I didn't consider when writing this in about 5 seconds -- so, don't disappoint me, fire away! :) )