Ha! that's me but I play the spacebar like I'm slappin' a bass guitar. It sounds awesome in my head...
Install a triggered directed boombox emitting a loud 'BANG' on registering that spacebar sound. Make it trigger only 35% of the time and with a variable 0-5 sec delay. I bet he stops using that spacebar by the end of the first day.
That's my microsoft ergo too. The giant spacebar is an echo chamber on its own.