The students in Tehran aren't fans of the government and were again out in force protesting. The government response: tear gas and billy clubs. From The Washington Post:
"Iranian security forces and paramilitary groups clashed with anti-government protesters in central Tehran on Monday, witnesses said, wielding batons, firing tear gas and stunning people with electrical batons to disperse crowds outside Tehran University.
Although security forces arrested dozens of demonstrators, crowds on the streets appeared to be growing, witnesses said. Roads were being blocked by security forces, preventing cars from entering the center of town.
Authorities cracked down on the "Student Day" demonstrations by warning ahead of time that such gatherings would be considered illegal and met by force. Thousands of demonstrators tried to meet up with students at sealed-off campuses of Tehran's main universities, but faced hundreds of riot police, Revolutionary Guard Corps forces and members of the Basij, a voluntary paramilitary arm of the Revolutionary Guards."
Read more on the government crackdown at WashingtonPost.com