I find most of my students seem to have no desire at all to hang out with their classmates outside class (too busy, terrible at socialising, "But I'm here to learn, not meet people!" and similar excuses) and given half a chance ignore them in class too. However, if learners in a classroom don't make the effort to get to know each other, there's little a teacher can do with the class.
Given the fundamental importance of the ice-breaking stage, my general rule is to spread it over two classes (I see classes for 50 minutes every day.). Everyone has their own little stash activities for this. Here's mine.
Preparation: gather together about half a dozen things you feel say something interesting about you. (I use things like my Korean cookbook (in Korean), the capo for my guitar (What is it??), a handful of postcards from back home, a novel in French, and (low denomination!) banknotes from some of the countries I've visited.)
1. Basic Introductions: everyone's name, jobs or degree courses, main interests and whereabouts they live. All this information should be written clearly (and in bright colours!) on folded pieces of paper that will be kept on the table for the next few lessons. To be friendly and co-operative, they can work in pairs to make these for each other; and then introduce each other to the class.
2. Hand out the objects you've prepared and get them into small groups to discuss what they think each thing says about the teacher. After they've passed round all the objects, ask the class for suggestions (most objects aren't difficult to figure out, but accept all guesses as possible). When you've had all comments in, better point out which guesses were right and which wrong, otherwise you might end up with misconceptions from the start. (Like the one student of mine who for two months thought I was actually French!)
3. If you have long enough you could go into a Needs Analysis discussion from here, or ask them to write about that individually for homework.
Preparation: make a sheet of intriguing questions! (One each or one between two. If you like, you can collect these in after the class so as not to waste paper.) The questions should all be up-beat and show real curiosity about the other person's values, interests and feelings. They can also be cheeky, flirtaceous, philosophical, whatever does it for you. (Lots of examples below.) About a dozen should give plenty of choice and ample opportunities to talk themselves and learn about each other.
1. Introduce this as an antidote to the tedious "Where are you from? What do you do?", and that they'll be rated on two things while they're getting to know each other better: listening and how much they can remember about their classmates, and the use of follow-up questions to keep the conversation going. Give out question sheets and don't interrupt unless called. This activity works best in small groups or pairs.
2. When they've had sufficient time, they can take it in turns telling the class the most interesting things they've learnt about the person/people they've talked to. If you have time, others can ask follow-up questions. Recommend that people who have something in common, or even the whole class, should go for a coffee (or tea) afterwards.
Example questions (Choose about a dozen. Tailor them to your class. Change wording or add definitions at the bottom of the question sheet if needed. Questions alone look dull - add a few pictures.)
What's your earliest memory?
Do you cry at sad films?
What's your worst habit?
In your opinion, what's the most important thing the opposite sex needs to learn?
What's your favourite thing to do to have fun and what attracts you to it?
A genie grants you one wish - what would it be?
What do you think is your most attractive feature?
Choose two words to describe yourself.
Who do you admire most in the world and why?
Which sense is most important to you?
Do you believe monogamy works?
What's your favourite thing to do on a date?
What's your biggest ambition?
What's the most beautiful thing you've ever seen?
I'm very slim. How can I put on weight?
What type of guy/girl do you go for?
Do you often get drunk?
What do you think of acupuncture?
What do you want for Christmas?
What's your favourite season, and why?
What comes to mind when I say "vacations"?
You fall in love with someone from another country - would you consider marriage?
Do you keep many secrets?
What comes to mind when I say "culture"?
What's your favourite TV in your country, and what's your favourite foreign one?
Are there any attractive men/women in your workplace?
How do you like to spend quiet time by yourself?
Would you date yourself?
If you could be the star of a film, what kind of film would it be?
Can you lend me a dollar?
What would you most like to find out?
Did you ever go on a school trip when you were younger?
What's your favourite place to eat?
Have you ever had a pen pal? Would you like one?
What were you like when you were younger?
Describe your ideal day.
What can you tell me about your country's culture?
What's the furthest you've ever been from home?
Do you have any role models?
What can you tell me about your best friend?
What comes to mind when I say "love"?
Tea or coffee?