Unfortunately, I haven't had the pleasure of trying a White Castle "slider" myself, but this family wanted to try it so bad that they created an Ebay Auction to finance the trip. But rather than just take the money, they'd set themselves a challenge. The three members of the family had to eat 100 sliders each, same day, without leaving the restaurant.
Globat.com decided to finance the trip, so long as they promoted their site along the way. They did, and after sitting in the same restaurant for 27 hours, they had a result...
From: http://www.youtube.com/watch?v=WE0nPbRdQNY