There are so many propositions
already, its doubtful that mine will even get noticed but I will give it a try anyway.
BitBooky - this one is available for almost all domains, only tweeter is taken
Bitnbook - also all versions available and looks like its free on social media
Blocksports - .com is taken but rest looks free.
And as a last proposition, the most simple and descriptive one:
btcsport(s)book - to my surprise all domains are ready to buy, (s) is optional doesn't change the availability.