I'd like to set up an "advanced search" page that would allow users to choose to filter posts displayed by categories. So, let's say I want to see all posts in "category1" and "category7" ... I'd check 1 and 7, hit submit and it'd display them.
Sounds easy. Is there a plugin for this? I thought an advanced-search plugin would work, but it seems it needs a search term to work--it doesn't want to "filter" categories without it.