I visited two small castles west of Frankfurt.
The first one is Schönbusch, part of a large park area close to Aschaffenburg. The main reason was for a photo shoot for a present for my sister. But as her birthday is in September I can't show you the present yet.
Second stop was Castle Mespelbrunn, a smallish castle which is still privately owned and lived in. In Germany it's most famous for being the set for a movie from the 60s (The Spessart Inn - Das Wirtshaus im Spessart)