Where can I find other adventures for Castle Ravenloft? So far I've only found the two bonus adventures that WotC released.
BoardGameGeek Castle RavenLoft has quite a few used-made scenarios and extra characters.
The most are listed in the Variants forum, although you may look around in there a bit and find some others under "rules" maybe.
One of my favorites is "Crypts And Creepers", although it's more of an 'expansion', not just another scenario.
Here's a link I just found that has most of the user-created adventures listed and ranked:
Update: link for "official" 2 bonus adventures is http://archive.wizards.com/DnD/Article.aspx?x=dnd/duad/20100816