This exercise is not so much for team building but maybe more for "breaking the ice" in a group of people that will need to spend time working together but may have just met. I participated in this during Red-Cross lifeguard training, and the trainer used it with fire-fighter teams.
Draw a thick likeline on the floor. The thickness should be a bit less than the length of your foot. Imagine it's a tree trunk laying on the floor (in fact, this exercise is usually done with a tree trunk)
Make everybody stand across that line/trunk.
Now tell everybody to re-arrange themselves in the "trunk" in alphabetical order, without "falling off the trunk" (or stepping out of the line)
In this exercise, people need to ask their names in order to know whether they are in the right position or not, and there is physical contact in order to keep the balance and not fall off the "trunk" (or the line/rectangle on the floor). This is a great exercise to do on day 1.
It might not work great with just 4 or 5 people, though.