Though not nearly as cool as the above build by R D L, on Saturday, October 18th from 12:00-2:00pm all Toys"R"Us locations are hosting a special building event where you can build and take home a Lego Bat-Signal. The stipulation is that this build is intended for children ages 5 and up, so, bring your kids unless you want to somehow convince them that you are a kid at heart.
The build, though pretty basic, has some really cool elements. The R2D2 legs in black are the first thing that stick out to me and the dish with the Bat-logo printed on it. It is free Lego, though, you shouldn't really pass it up.
Of course, if they have any left, you should try and take advantage of the bricktober promotion where you get a Toys"R"Us exclusive mini-modular building with $75 purchase. Please make sure you are not paying more than RPP (Retail Purchase Price) for your Lego sets though. Toys"R"Us is notorious for marking Lego up ridiculous amounts.