This is my weird incarnation of a lan box (yeah get it?, hilarious). I used to take a gaming laptop to lans for many years, but a good while ago sold that laptop, and also wasn't attending lan parties anymore, really.
But then spontaneously one popped up on the horizon and I figured I somehow had to come up with a system capable of playing the games we were gonna play. An ultrabook wouldn't cut it (in hindsight, it would, but I didn't know that yet).
I didn't want to spend too much, and the smallest motherboard I had was an mATX flavor AM3+ board. Combined with an FX8120 and 16GB DDR3 this thing was not exactly going to be a powerhouse, but it would do. I used the ASUS GTX660 DC2 yet again at first, and reused a Wraith Prism cooler for the CPU (hint: it's sparkly, but it can't handle a power sucking Bulldozer...).
The tricky part were the peripherals. I didn't want to have to move around a whole setup in pieces, so I figured I'd try to mount the monitor to the backside of the case. A few dremel holes and a VESA mount later, the deed was done. The center of mass is dangerously veered towards the back, but it stands upright on its own, good enough.
The case I used is a Q300L, and I picked it because Cooler Master had promised the ability to purchase various extension parts for it, most notably a handle that can mount at the top. Unfortunately it turned out they wouldn't release any handle until months after the lan party, and even when they did, they were only intended as replacements for the Q300 handles and didn't come with mounting hardware...Go CM...
Nothing zipties and a cheap handle can't fix, and so eventually the monstrosity that is this computer was alive.
What I've changed since then is I swapped the cooler for an old Mugen 3 with an eloop B12, and swapped the GTX660 with an RX570 8GB I got on sale. ...and then I swapped the whole cooling setup again to liquid cooling.