Because my working environment is a strong advocate of team learning, I have been experimenting with group activities…some of which actually work. Looking back through my notes, I think the ones that generate the most excitement (and hence talking) from the students are ones which build on something they already know well (like Thanksgiving).
For reasons I discuss below, most focus on sociolinguistics instead of topics like phonetics or syntax which tend to require more formal “mathematical” machinery.

Thanksgiving Ethnography

I asked students to get in groups and compare Thanksgiving traditions based on several dimensions such as patterns in dinner table conversation (topic, formality, interruptions) and treatment of older relatives (as well as side dishes). It’s a chance for students to see cultural differences in linguistic behavior.

“New Jerseyite” vs. “New Jerseyan”

I first asked students to look up “New Jerseyite” and “New Jerseyan” on Google to determine which form was “correct”. Since students used different strategies, I asked them to meet in groups to discuss how they approached the question then we did a summary. In this activity we generally have a good discussion of “prescriptive” vs. “descriptive” grammar since the dictionary mandates “New Jerseyite” but all native New Jerseyans unilaterally reject the word.

Color Chart

I split the group into men and women and asked each group to assign labels to a color wheel with 12 colors. Unlike the stereotype that “women know more color words”, both men and did equally well in this case. My point here was that individuals can diverge from “group” norms in their behavior.

Investigating Missing Fudge

In terms of an online discussion forum, I found that I got the most passionate answers when students were asked to discuss how they would ask roommates about missing fudge. Answers ranged from expected indirect questioning to outright accusations (but only if they knew the person well).

Why I think they worked

I think students found these the most exciting because they were asked to analyze a “common” situation in a brand new way. Not only did students see connections with the content, but scaffolding was built in. Students were able to take old concepts and critically think about them. With newly learned data, critical thinking seems to be harder.
I have done semi-successful group activities based on new data, but the excitement is not the same and you do often see students who don’t participate because they feel lost. It’s not the same.
One of the more interesting cases was when I asked students to solve a morphology problem in pairs (think algebra but with letters). Unlike other activities, students immediately fell silent and worked on the problem individually instead of talking to each other. In this case, their instinct was to work it out “on their own”.
When one instructor told me that she dropped discussion in her Gen Ed class, I wasn’t surprised that her reason was “the students didn’t know enough.” At the Gen Ed stage, students may still be stuck in the low level knowledge and fact stage and not yet to advance to a higher level on content alone. A connection to something they already knew in daily life may have been needed.
As for critical thinking outside “daily life”, maybe that IS something that needs to wait a semester (or at least a few weeks). There may be a time issue involved in moving from level to level.
I’m always amused when a paper talks about the benefits of class discussion and the example comes from a graduate level class. If they’ve made it to graduate school, we can be sure they’ve mastered most of the lower level content already!