Magnetic number fishing, they add what they catch! As well as addition, develops hand/eye coordination, fine motor--I love this for magnetic letter fishing too! When they catch a letter, they say its name and sound.
button snake - fine motor activity for teaching buttoning skills (happy hooligans) what a great craft idea for camping trip . doesn't take up a lot of space and the toddlers love the twirly effect that the snake makes when done.
Measurement Inquiry - For CAP classrooms, this could double in the discovery center with a graph (children put their name under the color they think has the most)-- Use non-breakable PLASTIC jars and hot glue the lids on.