Lego Joker Mini Mech Bot
It was pretty cool, you just went in and they had all the pieces in separate boxes. You just grabbed an instruction sheet and got to building.
You could build it there or toss the pieces into a baggie and build it later. I brought Toyriffic's intern in with me (so I wouldn't be booted out for being too old!) and she helped me build it, but had little interest in the final product. She just likes all the tiny pieces.
I think Toys R Us has done this type of free build thing before, but I never really took notice. But since this one was DC themed, it got my attention, and I'm glad it did. I'm going to try and keep tabs on them from now on so I don't miss out!