I play a game with the kids where I say a colour and they have to run and get me something of that colour (if in the classroom) or run and touch something of that colour (if in the recreation area)
Otherwise you could do a colouring exercise I've just posted on this site in the worksheet section. I've called it house-colour. (By the way, I didn't prepare this material and I can't remember where I got it from so I apologise in advance for posting it under my name)
How about The Rainbow Song here:
http://www.britishcouncil.org/kids-s...bow-lyrics.pdf
and then colour a rainbow to put up in class.
Hope that helps