Recently there was a discussion in the ##XNA channel on Freenode about how to constrain the mouse to the game-window. The solution proved to be non-obvious and required a little bit of creativity to implement.
I had a very nice design and setup ready for my Hextille project when I decided to dabble with serialization. Like the old sweater where you pull on one string only to dislodge another, my design had to change to allow for serialization. In the end, I just wanted to scream “Not now, silent singer. Not now!” Basically what I want to accomplish is to serialize a graph (vertices and edges) including support for cyclic references, generics, child nodes, enumerated types, etc.