Magformers are basically the best kids' toy ever. I am not exaggerating that. They're colorful shapes with rotating magnets in the edges, so you can use them to build all sorts of structures and to let your kids experiment with the basic principles of magnets. They're super easy for little fingers to manage and provide endless fun. Plus, my husband (who hates most toddler toys) will play with them even without our daughter around!
They're not supposed to be for children under three years old because of the potential for swallowed magnets. However, they seem solid enough that I feel comfortable giving them to my one year old as long as she has some supervision, on the off-chance that she manages to break them open and swallow a magnet inside. You'll have to make that decision yourself, but it is VITAL that you never let your child swallow any magnets, from this or any other toy. That would be very bad.
We got the basic 62 piece set for $64 on amazon but there are many other options you could select to make sure you have the right amount for your kids, from the 30 piece set to the intense 300 piece set.
Happy building! (Even though it's totally for the kids...yeah...just for them.)