ReadWriteThink
Read Write Think: A Mini Lesson on Semicolons
Practical instructional activity on students' use of the semicolon, modeled on Martin Luther King's "Letter from a Birmingham Jail."
Other
Tidewater Community College Writing Center: Practical Punctuation Guide
This site contains practical and useful information about the following: commas, semicolons, colons, dashes, parentheses and brackets, ellipsis points, quotation marks, and apostrophes. CCSS.ELA-Literacy.CCRA.L.2