I am a big fan of board games and card games. I also really enjoy making my own expansions for them. Here you will find links to the posts containing these custom expansions.
Card Game Expansions:
BANG! Cusp of Carabelli
Board Game Expansions:
The Heroscape Blog
Pandemic Custom Role: Bacteriologist
Settlers of Catan Oil Springs Modification
Teenage Mutant Ninja Turtles: Shadows of the Past Custom Slash Ally Card