Free Mojtaba and Arash Day.
From the BBC (with link):
The global web blog community is being called into action to lend support to two imprisoned Iranian bloggers.
The month-old Committee to Protect Bloggers is asking those with blogs to dedicate their sites on 22 February to the 'Free Mojtaba and Arash Day'.
Arash Sigarchi and Mojtaba Saminejad are both in prison in Iran.
... The group has a list of actions which it says bloggers can take, including writing to local Iranian embassies...