So a few months back, I bought $500 worth of Lego sets for my class and the other preschool class. This was possibly the best toy purchase I've ever made for a classroom. We put one set on the shelf right after we got them in, and they have been played with EVERYDAY!
At first, I was like, "Oh, they're just the new toy so everyone is excited about them." And that is usually how things go with new toys in the room. They get old after a couple weeks and there start being days where certain toys aren't even touched. So that's why we rotate toys in the preschool rooms a lot because kids get bored of the same ol toys day in and day out. New toys or even re-introduced toys keep kids engaged and out of trouble.
But...we've had the same Lego set out since we got it in, and every single day it is taken out and played with. On Friday, it was nearly the only toy played with ALL DAY. One girl plays nearly exclusively with Legos. My co-teacher and I tried thinking of other things she has played with in the room, and we couldn't come up with much. All this after we have completely rearranged our dramatic play area with more kitchen toys and dress-up clothes. The girl still just wants the Legos, lol.
We've played with the special construction Duplo set I bought a few times, but I have to sit right with them and help them build things so sometimes it isn't the best thing to get out. The other Lego set that's just for building cars is still brand new and ready to go, but I was waiting for them to tire of the first set. I'm not sure that's going to happen lol.
This is what has held their attention for so long: (we just dumped the set of Lego figures in the blue tub)
http://www.amazon.com/gp/product/B002UD8P4S/ref=oh_details_o04_s01_i00
http://www.amazon.com/gp/product/B004GUMGK2/ref=oh_details_o04_s00_i01