"If someone from the 1950s suddenly appeared today,
what would be the most difficult thing to explain
to them about today?"
"I possess a device, in my pocket, that is capable
of accessing the entirety of information known to
man. I use it to look at pictures of cats and get
into arguments with strangers."
Nope, you need to have contents in Catalan in your .cat site, not for six months but forever. I couldn't find this 6-months clause anywhere, and the terms don't mention it at all: http://fundacio.cat/ca/domini/sobre-el-cat/normativa
Furthermore, they clearly say that violation of the only usage restriction (contents in Catalan) can result in your domain being suspended.
edit: Just a little correction to your text in Catalan: L'idioma català és una llengua bonica. ;)
>> I couldn't find this 6-months clause anywhere ..
Actually if you try to add a *.cat domain through gandi.net, they included this clause as a tip-text encoded in the little warning image: "Warning: the registration contract for domain names in this extension require that you publish at least one page in Catalan within 6 months."