I posted about people using rubber ball instead of a chair. I found a chair that require you t balance. It is called "Swopper". Other than the fact it cost $550 to $1000, it looks like a good office chair.
シェア
落語好きプロコーチ 砂村よしお 
SanDiegoTown & LosAngelesTown 
さわ 
Seattle Execs. 
さち 
Tetsuro Watanabe 
あさこ 
ClockLink 
錦糸町の天使 
佐藤淳一（朝活習慣化キャリアコーチ） 
コーチ探せる