Thousands demonstrate in Tahrir Square : Ivan Watson

Cairo, Egypt (CNN) -- Thousands of demonstrators gathered in Cairo's famous Tahrir Square on Friday, as part of an effort by liberal activists to revive their movement after a series of perceived political set-backs.

Dubbed the "Friday to Save the Revolution," the rally is an effort to show opposition to a recent proposed law which would criminalize protests. It is also an effort to re-assert the youth movement which drove former president Hosni Mubarak from power.

Many liberal activists fear they have been side-lined since Mubarak's February 11 overthrow by Egypt's ruling military council and by more politically-experienced Islamist groups, well disciplined after operating for decades in secret while facing harsh persecution.