I teach more kids than adults, so I �ll offer what nuggets of wisdom I have.
I usually...
1)   	We play WHAT �S YOUR *** NAME? (*** topic chosen by teacher)   I �m Matt - M is for 	monkey (I chose animals as an example, but you could use 	any lexical set you want) 	so for today you should call me Matt Monkey - and I will call you all by your animal 	name.
2)	Kids in a circle.  Hands, palm up on your knees.  Put your left hand ON the right hand of 	the person on your left - put your RIGHT HAND UNDER the left hand of the person on 	your 	left.  
	Go around the circle passing a hand clap across to the partner (from your left hand 	onto the right hand of the person next to you) and count from 1 - 10 (or 20, or 15 or 	whatever	the teacher chooses).  Once the group has gone around the circle a few 	times there are a number of speed-bumps you can throw in...like replace numbers with 	words...1,2,banana,4,5,pineapple etc.  Introduce the challenges one at a time though, 	or it can be overwhelming to remember;)
3)	Getting into groups activity:  MUSICAL NUMBERS.  Play an upbeat song and have the 	students move/dance/walk around the room.  Teacher stops the music and calls out a 	number.  Students then get into groups of that number.  Repeat with a few variations 	before settling on the number of groups you need for the activity to follow.
4)	In groups, have brainstorm some ideas for GOOD BEHAVIOR/HABITS for a student in 	the classroom.  RULES basically, but it �s modelling the positive behavior.  You might 	want to introduce your own classroom reward system at this point too. 
	To share my reward system:  I made "Matt Money".  I bought some cheap candy and 	pencils/books/small prizes. I assigned each prize a value.  Students in my class (from 5 	years old and up) achieve little fake banknotes.  Money can be saved up to buy a more 	expensive prize - like a pretty pencil (I �m in China, stuff is cheap!) or an interesting 	eraser etc, or they can use it straight away for stickers/cheap candy (just 1 per note!).  	And WOW can these kids save it up!  I promised them ice-cream from McD �s if they 	saved up 50MM!  Of course, start off the reward system making it quite easy to achieve 	... but get gradually more reserved with your rewards...make it more challenging to get 	the rewards, but always a positive experience.
5)	We round off the GOOD BEHAVIORS by doing "Classroom Instructions" activity.  
	Teacher calls out a high-frequency instruction:  Stand Up, Take out your books, Put 	your book under your chair etc.  Every so often I �ll toss in something silly:  Put your 	pencil under your chair, stand on 1 leg.   
Hope that helps.  If you want more, I �ll be happy to help.  The above would take around an hour.