Hard by the Boston University campus, the medium-size Paradise draws enthusiastic, student-intensive crowds for top local rock and alternative performers. You might also see national names (lately, Edwin McCain, Beth Orton, and the Wallflowers) who want a relatively small venue, and others who aren't ready to headline a big show on their own (Sister Hazel, the Donnas, the Soundtrack of Our Lives). Most shows are 18-plus. You must be 21 to drink alcohol, a policy that became iron-clad here after a months-long "vacation" courtesy of the Boston Licensing Board; don't forget your ID.