So we all know of IE6 and the problem it can have have when you have multiple submit buttons on a form and you press enter in an edit control. IE6 gets confused over what button should be sent to the server as the submit button. This annoyance is covered here and here.
The issue I had recently was that even though I was directly clicking on a button (the search button on this page) ASP.NET was firing the code for the final button on the page (which in this instance was a "Finish" button). Once I realised that this is what was happening i took a look at the form that was being posted to the server. In the form variables collection I found both button elements! This is is an IE6 only issue and darn annoying.
The fix was to disable the unneeded buttons, which stops them being included as part of the form post. More specifically I hook the click event on all the input and button elements, of type "submit", on the page, when it first loads. Then when the click happens I disable all the button elements and reenable them using setTimeout after 2 seconds.
The only exception to this disabling is if it was a button that caused the click. That button is obviously not disabled.
You can see the solution on this page here http://www.ditto.net/Topics/MoviesMakeMeLaugh/fill in the function hookAllButtonsForDisabling().