What are the best adaptations of the game of Chess?

For example: The Star Trek and 3 dimensional chess variations.

there-are-over-15,000-variants.about-20-have-some-popularity.my-favorites-are-bughouse-and-progressive.

Atomic Chess I found was interesting.  It's played to the same rules except for one difference.  Each player has an atomic weapon assigned to one of their pieces, only they know which one (obviously).  It can be detonated at any time, only once, and it takes out every piece on the surrounding squares.  I nearly fell off my chair laughing reading the rules because there was a disclaimer at the bottom stating that this game was not inspired by suicide bombers.