In universities, how to team up with your colleagues?
In our department, the assistant professors go out for drinks once a month (a fixed day of the week and a fixed week of the month). That tends to work out quite well: we can let off steam, compare notes on our students (and what senior faculty dish out in the name of advice :)), and generally get a nice group. I've had a few collaborations start because of this as well. 

The general faculty also do a drinks night occasionally, but not as regularly.