This series of drawings struck me as something that might be useful to spawn conversation. Some Drawings are more controversial than others, but several hit on topics that I think some classes are already discussing, especially the upper levels.
This is a fun video about the function of the comma in compound and complex sentences. Good for review. Questions are customizable if you register your name and e-mail.
I found this awesome vocab tool that picks out important words in an online (or typed in) text based on relevance, frequency, and subject. It creates word clouds (don't worry, I didn't know what those were either), gives definitions, parts of speech, and examples from the text. The full features are only available with a paid subscription, but there's a lot you can do with the free version, too, and you don't even need to create a username or password! This could be a very helpful website to pass on to students.