Making students pray in school, as part of the curriculum and/or normal school day.
Inserting religion-based speculations into science classes, as if they have the same legitimacy there as actual science.
Allowing religion-based school clubs, while denying said organization to other groups, such as the GLBT (Gay Lesbian Bisexual Transsexual) students, for example.
Opening a secular activity with prayer.
Company get-togethers (like holiday banquets, picnics, and softball games) which an employee is expected to attend, but which are loaded with overtones and outright declarations of the boss' religion.
And, frankly, any secular, non-religious activity I am expected to attend or required to attend. If you can force me to be there, I will really resent your foisting your religion on me.