Sporadically, I am receiving "out of memory" errors on my websites. In my performance monitor (Debug Diagnostic Tool), I can watch virtual bytes skyrocket until it causes an "out of memory" error on my website.

What could be causing this? Even if I have piss-poor code with plenty of unclosed, un-nothing'ed objects, shouldn't the memory be freed after the page is served to the user? That is, nothing should be...