One corkscrew design I’ve never been able to master is the Ah So.  Supposedly great for old wines with corks of questionable integrity, more often than not I end up pushing the cork down rather than pulling it out.  Greg Del Pias, Community Manager at Snooth, and host of the NY Wine Century Club gathering demonstrates a little trick using the Screwpull worm.  Check out the video here:
http://www.youtube.com/watch?v=fBdgn3AlkYo