My 4th/5th grade classroom has a class of kindergarten buddies. Every other week, I make up activities to do with them. I created a Worm packet to use during the year. The packet includes a reader that focuses on colors and critters, a gummy worm lab sheet, and a worm glyph project. My kids complete all of these activities with our kindergarten buddies in one 45 minute period and help the little ones to do the work.
If you have not tried having your intermediate classroom "adopt" a younger buddy class, you should! It is a great experience for both groups of kids!