So, I did it. I made it so that I could show a bunch of radio buttons reflecting categories in the database. It uses the auto-postback feature of the radiolist thingy so that when you click on a radio, it auto-reloads the page.

Hey, it's not much, but if I had the patience to tell you about all of the hassles (values in sql-type queries are strongly typed, where clause comparisons use '==', not '=', etc), you'd be proud.