Lexus commissioned a fully functional electric car built from laser cut cardboard. It comprises 1700 individual pieces and took 3 months, I imagine the builders were quite card-bored by the end of assembly.
Another post from the laser cutting group now, Jocelyn has shared these Christmas letters and is currently working to complete the set. I hadn't realised how early people start working towards Christmas craft faires until I started reading these groups but I guess it makes sense. I'll keep you posted as to when the rest of the set it released assuming they letter do it amidst all the requests.
Instructables user JackCarter made this awesome lasercut tank model from MDF. The functional tracks looks great and the laser is perfect for making a repetitive object like that, although they do also provide the files to make a static track if you don't have enough patience for assembly. There are lots of tank models out there but, because this comes with instructions, it is definitely a challenger for the best.
There are a couple of giant hand builds around but I like this one from instructables user musicandsky because they've gone for a purely Halloween theme scare style. When combined with the skull mask, I imagine they had a lot of fun out and about in the evening. You'd have to pick your party carefully though, they should be good with finger food but undoubtedly clawful with drinks.