I know I have posted about our love for Tinkertoys before, but we just love these so much that I must mention them again!! For over an hour the boys have been playing with this "lawn mower" that I built them (by request). One of my rules for toys is that it should have multiple purposes (of course we break this rule for cars and trains and such, but I try to live by it).
If we had a toy lawn mower it wouldn't be played with anymore. They boys would have played with it a few times. Each time would have gotten progressively shorter until it was left sitting outside and never touched (unless perhaps a cousin or friend came over and wanted to use it and then they would fight over it for a while and then ignore it for something else, like a pile of sticks or a ball).
That's what is great about Tinkertoys, once they are finished with this in a few hours, we take it apart and either put It away or turn it into something else. It never gets old. It keeps their minds working.
We also love our Tegu magnetic blocks, regular blocks, and Trio blocks.
Speaking of toys with multiple purposes, have you see the new Lego sets that can be turned into three differnt things (such as a plane, tractor, and excavator)? I always found Legos frustrating because once you built something it just sat around built. Who wants to take it apart after all that work? I could live with Legos that you can take apart and rebuild into other creations.